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+<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"
+[<!ENTITY % poky SYSTEM "../poky.ent"> %poky; ] >
+<!--SPDX-License-Identifier: CC-BY-2.0-UK-->
+
+<chapter id='migration'>
+<title>Migrating to a Newer Yocto Project Release</title>
+
+    <para>
+        This chapter provides information you can use to migrate work to a
+        newer Yocto Project release.  You can find the same information in the
+        release notes for a given release.
+    </para>
+
+<section id='general-migration-considerations'>
+    <title>General Migration Considerations</title>
+
+    <para>
+        Some considerations are not tied to a specific Yocto Project
+        release.
+        This section presents information you should consider when
+        migrating to any new Yocto Project release.
+        <itemizedlist>
+            <listitem><para><emphasis>Dealing with Customized Recipes</emphasis>:
+                Issues could arise if you take older recipes that contain
+                customizations and simply copy them forward expecting them
+                to work after you migrate to new Yocto Project metadata.
+                For example, suppose you have a recipe in your layer that is
+                a customized version of a core recipe copied from the earlier
+                release, rather than through the use of an append file.
+                When you migrate to a newer version of Yocto Project, the
+                metadata (e.g. perhaps an include file used by the recipe)
+                could have changed in a way that would break the build.
+                Say, for example, a function is removed from an include file
+                and the customized recipe tries to call that function.
+                </para>
+
+                <para>You could "forward-port" all your customizations in your
+                recipe so that everything works for the new release.
+                However, this is not the optimal solution as you would have
+                to repeat this process with each new release if changes
+                occur that give rise to problems.</para>
+
+                <para>The better solution (where practical) is to use append
+                files (<filename>*.bbappend</filename>) to capture any
+                customizations you want to make to a recipe.
+                Doing so, isolates your changes from the main recipe making
+                them much more manageable.
+                However, sometimes it is not practical to use an append
+                file.
+                A good example of this is when introducing a newer or older
+                version of a recipe in another layer.</para>
+                </listitem>
+            <listitem><para><emphasis>Updating Append Files</emphasis>:
+                Since append files generally only contain your customizations,
+                they often do not need to be adjusted for new releases.
+                However, if the <filename>.bbappend</filename> file is
+                specific to a particular version of the recipe (i.e. its
+                name does not use the % wildcard) and the version of the
+                recipe to which it is appending has changed, then you will
+                at a minimum need to rename the append file to match the
+                name of the recipe file.
+                A mismatch between an append file and its corresponding
+                recipe file (<filename>.bb</filename>) will
+                trigger an error during parsing.</para>
+                <para>Depending on the type of customization the append file
+                applies, other incompatibilities might occur when you
+                upgrade.
+                For example, if your append file applies a patch and the
+                recipe to which it is appending is updated to a newer
+                version, the patch might no longer apply.
+                If this is the case and assuming the patch is still needed,
+                you must modify the patch file so that it does apply.
+                </para></listitem>
+        </itemizedlist>
+    </para>
+</section>
+
+<section id='moving-to-the-yocto-project-1.3-release'>
+    <title>Moving to the Yocto Project 1.3 Release</title>
+
+    <para>
+        This section provides migration information for moving to the
+        Yocto Project 1.3 Release from the prior release.
+    </para>
+
+    <section id='1.3-local-configuration'>
+        <title>Local Configuration</title>
+
+        <para>
+            Differences include changes for
+            <link linkend='var-SSTATE_MIRRORS'><filename>SSTATE_MIRRORS</filename></link>
+            and <filename>bblayers.conf</filename>.
+        </para>
+
+        <section id='migration-1.3-sstate-mirrors'>
+            <title>SSTATE_MIRRORS</title>
+
+            <para>
+                The shared state cache (sstate-cache), as pointed to by
+                <link linkend='var-SSTATE_DIR'><filename>SSTATE_DIR</filename></link>,
+                by default now has two-character subdirectories to prevent
+                issues arising from too many files in the same directory.
+                Also, native sstate-cache packages, which are built to run
+                on the host system, will go into a subdirectory named using
+                the distro ID string.
+                If you copy the newly structured sstate-cache to a mirror
+                location (either local or remote) and then point to it in
+                <link linkend='var-SSTATE_MIRRORS'><filename>SSTATE_MIRRORS</filename></link>,
+                you need to append "PATH" to the end of the mirror URL so that
+                the path used by BitBake before the mirror substitution is
+                appended to the path used to access the mirror.
+                Here is an example:
+                <literallayout class='monospaced'>
+     SSTATE_MIRRORS = "file://.* http://<replaceable>someserver</replaceable>.tld/share/sstate/PATH"
+                </literallayout>
+            </para>
+        </section>
+
+        <section id='migration-1.3-bblayers-conf'>
+            <title>bblayers.conf</title>
+
+            <para>
+                The <filename>meta-yocto</filename> layer consists of two parts
+                that correspond to the Poky reference distribution and the
+                reference hardware Board Support Packages (BSPs), respectively:
+                <filename>meta-yocto</filename> and
+                <filename>meta-yocto-bsp</filename>.
+                When running BitBake for the first time after upgrading,
+                your <filename>conf/bblayers.conf</filename> file will be
+                updated to handle this change and you will be asked to
+                re-run or restart for the changes to take effect.
+            </para>
+        </section>
+    </section>
+
+    <section id='1.3-recipes'>
+        <title>Recipes</title>
+
+        <para>
+            Differences include changes for the following:
+            <itemizedlist>
+                <listitem><para>Python function whitespace</para></listitem>
+                <listitem><para><filename>proto=</filename> in <filename>SRC_URI</filename></para></listitem>
+                <listitem><para><filename>nativesdk</filename></para></listitem>
+                <listitem><para>Task recipes</para></listitem>
+                <listitem><para><filename>IMAGE_FEATURES</filename></para></listitem>
+                <listitem><para>Removed recipes</para></listitem>
+            </itemizedlist>
+        </para>
+
+        <section id='migration-1.3-python-function-whitespace'>
+            <title>Python Function Whitespace</title>
+
+            <para>
+                All Python functions must now use four spaces for indentation.
+                Previously, an inconsistent mix of spaces and tabs existed,
+                which made extending these functions using
+                <filename>_append</filename> or <filename>_prepend</filename>
+                complicated given that Python treats whitespace as
+                syntactically significant.
+                If you are defining or extending any Python functions (e.g.
+                <filename>populate_packages</filename>, <filename>do_unpack</filename>,
+                <filename>do_patch</filename> and so forth) in custom recipes
+                or classes, you need to ensure you are using consistent
+                four-space indentation.
+            </para>
+        </section>
+
+        <section id='migration-1.3-proto=-in-src-uri'>
+            <title>proto= in SRC_URI</title>
+
+            <para>
+                Any use of <filename>proto=</filename> in
+                <link linkend='var-SRC_URI'><filename>SRC_URI</filename></link>
+                needs to be changed to <filename>protocol=</filename>.
+                In particular, this applies to the following URIs:
+                <itemizedlist>
+                    <listitem><para><filename>svn://</filename></para></listitem>
+                    <listitem><para><filename>bzr://</filename></para></listitem>
+                    <listitem><para><filename>hg://</filename></para></listitem>
+                    <listitem><para><filename>osc://</filename></para></listitem>
+                </itemizedlist>
+                Other URIs were already using <filename>protocol=</filename>.
+                This change improves consistency.
+            </para>
+        </section>
+
+        <section id='migration-1.3-nativesdk'>
+            <title>nativesdk</title>
+
+            <para>
+                The suffix <filename>nativesdk</filename> is now implemented
+                as a prefix, which simplifies a lot of the packaging code for
+                <filename>nativesdk</filename> recipes.
+                All custom <filename>nativesdk</filename> recipes, which are
+                relocatable packages that are native to
+                <link linkend='var-SDK_ARCH'><filename>SDK_ARCH</filename></link>,
+                and any references need to be updated to use
+                <filename>nativesdk-*</filename> instead of
+                <filename>*-nativesdk</filename>.
+            </para>
+        </section>
+
+        <section id='migration-1.3-task-recipes'>
+            <title>Task Recipes</title>
+
+            <para>
+                "Task" recipes are now known as "Package groups" and have
+                been renamed from <filename>task-*.bb</filename> to
+                <filename>packagegroup-*.bb</filename>.
+                Existing references to the previous <filename>task-*</filename>
+                names should work in most cases as there is an automatic
+                upgrade path for most packages.
+                However, you should update references in your own recipes and
+                configurations as they could be removed in future releases.
+                You should also rename any custom <filename>task-*</filename>
+                recipes to <filename>packagegroup-*</filename>, and change
+                them to inherit <filename>packagegroup</filename> instead of
+                <filename>task</filename>, as well as taking the opportunity
+                to remove anything now handled by
+                <filename>packagegroup.bbclass</filename>, such as providing
+                <filename>-dev</filename> and <filename>-dbg</filename>
+                packages, setting
+                <link linkend='var-LIC_FILES_CHKSUM'><filename>LIC_FILES_CHKSUM</filename></link>,
+                and so forth.
+                See the
+                "<link linkend='ref-classes-packagegroup'><filename>packagegroup.bbclass</filename></link>"
+                section for further details.
+            </para>
+        </section>
+
+        <section id='migration-1.3-image-features'>
+            <title>IMAGE_FEATURES</title>
+
+            <para>
+                Image recipes that previously included "apps-console-core"
+                in <link linkend='var-IMAGE_FEATURES'><filename>IMAGE_FEATURES</filename></link>
+                should now include "splash" instead to enable the boot-up
+                splash screen.
+                Retaining "apps-console-core" will still include the splash
+                screen but generates a warning.
+                The "apps-x11-core" and "apps-x11-games"
+                <filename>IMAGE_FEATURES</filename> features have been removed.
+            </para>
+        </section>
+
+        <section id='migration-1.3-removed-recipes'>
+            <title>Removed Recipes</title>
+
+            <para>
+                The following recipes have been removed.
+                For most of them, it is unlikely that you would have any
+                references to them in your own
+                <link linkend='metadata'>Metadata</link>.
+                However, you should check your metadata against this list to be sure:
+                <itemizedlist>
+                    <listitem><para><emphasis><filename>libx11-trim</filename></emphasis>:
+                        Replaced by <filename>libx11</filename>, which has a negligible
+                        size difference with modern Xorg.</para></listitem>
+                    <listitem><para><emphasis><filename>xserver-xorg-lite</filename></emphasis>:
+                        Use <filename>xserver-xorg</filename>, which has a negligible
+                        size difference when DRI and GLX modules are not installed.</para></listitem>
+                    <listitem><para><emphasis><filename>xserver-kdrive</filename></emphasis>:
+                        Effectively unmaintained for many years.</para></listitem>
+                    <listitem><para><emphasis><filename>mesa-xlib</filename></emphasis>:
+                        No longer serves any purpose.</para></listitem>
+                    <listitem><para><emphasis><filename>galago</filename></emphasis>:
+                        Replaced by telepathy.</para></listitem>
+                    <listitem><para><emphasis><filename>gail</filename></emphasis>:
+                        Functionality was integrated into GTK+ 2.13.</para></listitem>
+                    <listitem><para><emphasis><filename>eggdbus</filename></emphasis>:
+                        No longer needed.</para></listitem>
+                    <listitem><para><emphasis><filename>gcc-*-intermediate</filename></emphasis>:
+                        The build has been restructured to avoid the need for
+                        this step.</para></listitem>
+                    <listitem><para><emphasis><filename>libgsmd</filename></emphasis>:
+                        Unmaintained for many years.
+                        Functionality now provided by
+                        <filename>ofono</filename> instead.</para></listitem>
+                    <listitem><para><emphasis>contacts, dates, tasks, eds-tools</emphasis>:
+                        Largely unmaintained PIM application suite.
+                        It has been moved to <filename>meta-gnome</filename>
+                        in <filename>meta-openembedded</filename>.</para></listitem>
+                </itemizedlist>
+                In addition to the previously listed changes, the
+                <filename>meta-demoapps</filename> directory has also been removed
+                because the recipes in it were not being maintained and many
+                had become obsolete or broken.
+                Additionally, these recipes were not parsed in the default configuration.
+                Many of these recipes are already provided in an updated and
+                maintained form within the OpenEmbedded community layers such as
+                <filename>meta-oe</filename> and <filename>meta-gnome</filename>.
+                For the remainder, you can now find them in the
+                <filename>meta-extras</filename> repository, which is in the
+                Yocto Project
+                <ulink url='&YOCTO_DOCS_OM_URL;#source-repositories'>Source Repositories</ulink>.
+            </para>
+        </section>
+    </section>
+
+    <section id='1.3-linux-kernel-naming'>
+        <title>Linux Kernel Naming</title>
+
+        <para>
+            The naming scheme for kernel output binaries has been changed to
+            now include
+            <link linkend='var-PE'><filename>PE</filename></link> as part of the
+            filename:
+            <literallayout class='monospaced'>
+     KERNEL_IMAGE_BASE_NAME ?= "${KERNEL_IMAGETYPE}-${PE}-${PV}-${PR}-${MACHINE}-${DATETIME}"
+            </literallayout>
+        </para>
+
+        <para>
+            Because the <filename>PE</filename> variable is not set by default,
+            these binary files could result with names that include two dash
+            characters.
+            Here is an example:
+            <literallayout class='monospaced'>
+     bzImage--3.10.9+git0+cd502a8814_7144bcc4b8-r0-qemux86-64-20130830085431.bin
+            </literallayout>
+        </para>
+    </section>
+</section>
+
+<section id='moving-to-the-yocto-project-1.4-release'>
+    <title>Moving to the Yocto Project 1.4 Release</title>
+
+    <para>
+        This section provides migration information for moving to the
+        Yocto Project 1.4 Release from the prior release.
+    </para>
+
+    <section id='migration-1.4-bitbake'>
+        <title>BitBake</title>
+
+        <para>
+            Differences include the following:
+            <itemizedlist>
+                <listitem><para><emphasis>Comment Continuation:</emphasis>
+                    If a comment ends with a line continuation (\) character,
+                    then the next line must also be a comment.
+                    Any instance where this is not the case, now triggers
+                    a warning.
+                    You must either remove the continuation character, or be
+                    sure the next line is a comment.
+                    </para></listitem>
+                <listitem><para><emphasis>Package Name Overrides:</emphasis>
+                    The runtime package specific variables
+                    <link linkend='var-RDEPENDS'><filename>RDEPENDS</filename></link>,
+                    <link linkend='var-RRECOMMENDS'><filename>RRECOMMENDS</filename></link>,
+                    <link linkend='var-RSUGGESTS'><filename>RSUGGESTS</filename></link>,
+                    <link linkend='var-RPROVIDES'><filename>RPROVIDES</filename></link>,
+                    <link linkend='var-RCONFLICTS'><filename>RCONFLICTS</filename></link>,
+                    <link linkend='var-RREPLACES'><filename>RREPLACES</filename></link>,
+                    <link linkend='var-FILES'><filename>FILES</filename></link>,
+                    <link linkend='var-ALLOW_EMPTY'><filename>ALLOW_EMPTY</filename></link>,
+                    and the pre, post, install, and uninstall script functions
+                    <filename>pkg_preinst</filename>,
+                    <filename>pkg_postinst</filename>,
+                    <filename>pkg_prerm</filename>, and
+                    <filename>pkg_postrm</filename> should always have a
+                    package name override.
+                    For example, use <filename>RDEPENDS_${PN}</filename> for
+                    the main package instead of <filename>RDEPENDS</filename>.
+                    BitBake uses more strict checks when it parses recipes.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-1.4-build-behavior'>
+        <title>Build Behavior</title>
+
+        <para>
+            Differences include the following:
+            <itemizedlist>
+                <listitem><para><emphasis>Shared State Code:</emphasis>
+                    The shared state code has been optimized to avoid running
+                    unnecessary tasks.
+                    For example, the following no longer populates the target
+                    sysroot since that is not necessary:
+                    <literallayout class='monospaced'>
+     $ bitbake -c rootfs <replaceable>some-image</replaceable>
+                    </literallayout>
+                    Instead, the system just needs to extract the output
+                    package contents, re-create the packages, and construct
+                    the root filesystem.
+                    This change is unlikely to cause any problems unless
+                    you have missing declared dependencies.
+                    </para></listitem>
+                <listitem><para><emphasis>Scanning Directory Names:</emphasis>
+                    When scanning for files in
+                    <link linkend='var-SRC_URI'><filename>SRC_URI</filename></link>,
+                    the build system now uses
+                    <link linkend='var-FILESOVERRIDES'><filename>FILESOVERRIDES</filename></link>
+                    instead of <link linkend='var-OVERRIDES'><filename>OVERRIDES</filename></link>
+                    for the directory names.
+                    In general, the values previously in
+                    <filename>OVERRIDES</filename> are now in
+                    <filename>FILESOVERRIDES</filename> as well.
+                    However, if you relied upon an additional value
+                    you previously added to <filename>OVERRIDES</filename>,
+                    you might now need to add it to
+                    <filename>FILESOVERRIDES</filename> unless you are already
+                    adding it through the
+                    <link linkend='var-MACHINEOVERRIDES'><filename>MACHINEOVERRIDES</filename></link>
+                    or <link linkend='var-DISTROOVERRIDES'><filename>DISTROOVERRIDES</filename></link>
+                    variables, as appropriate.
+                    For more related changes, see the
+                    "<link linkend='migration-1.4-variables'>Variables</link>"
+                    section.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+
+    <section id='migration-1.4-proxies-and-fetching-source'>
+        <title>Proxies and Fetching Source</title>
+
+        <para>
+            A new <filename>oe-git-proxy</filename> script has been added to
+            replace previous methods of handling proxies and fetching source
+            from Git.
+            See the <filename>meta-yocto/conf/site.conf.sample</filename> file
+            for information on how to use this script.
+        </para>
+    </section>
+
+    <section id='migration-1.4-custom-interfaces-file-netbase-change'>
+        <title>Custom Interfaces File (netbase change)</title>
+
+        <para>
+            If you have created your own custom
+            <filename>etc/network/interfaces</filename> file by creating
+            an append file for the <filename>netbase</filename> recipe,
+            you now need to create an append file for the
+            <filename>init-ifupdown</filename> recipe instead, which you can
+            find in the
+            <link linkend='source-directory'>Source Directory</link>
+            at <filename>meta/recipes-core/init-ifupdown</filename>.
+            For information on how to use append files, see the
+            "<ulink url='&YOCTO_DOCS_DEV_URL;#using-bbappend-files'>Using .bbappend Files</ulink>"
+            section in the Yocto Project Development Tasks Manual.
+        </para>
+    </section>
+
+    <section id='migration-1.4-remote-debugging'>
+        <title>Remote Debugging</title>
+
+        <para>
+            Support for remote debugging with the Eclipse IDE is now
+            separated into an image feature
+            (<filename>eclipse-debug</filename>) that corresponds to the
+            <filename>packagegroup-core-eclipse-debug</filename> package group.
+            Previously, the debugging feature was included through the
+            <filename>tools-debug</filename> image feature, which corresponds
+            to the <filename>packagegroup-core-tools-debug</filename>
+            package group.
+        </para>
+    </section>
+
+    <section id='migration-1.4-variables'>
+        <title>Variables</title>
+
+        <para>
+            The following variables have changed:
+            <itemizedlist>
+                <listitem><para><emphasis><filename>SANITY_TESTED_DISTROS</filename>:</emphasis>
+                    This variable now uses a distribution ID, which is composed
+                    of the host distributor ID followed by the release.
+                    Previously,
+                    <link linkend='var-SANITY_TESTED_DISTROS'><filename>SANITY_TESTED_DISTROS</filename></link>
+                    was composed of the description field.
+                    For example, "Ubuntu 12.10" becomes "Ubuntu-12.10".
+                    You do not need to worry about this change if you are not
+                    specifically setting this variable, or if you are
+                    specifically setting it to "".
+                    </para></listitem>
+                <listitem><para><emphasis><filename>SRC_URI</filename>:</emphasis>
+                    The <filename>${</filename><link linkend='var-PN'><filename>PN</filename></link><filename>}</filename>,
+                    <filename>${</filename><link linkend='var-PF'><filename>PF</filename></link><filename>}</filename>,
+                    <filename>${</filename><link linkend='var-P'><filename>P</filename></link><filename>}</filename>,
+                    and <filename>FILE_DIRNAME</filename> directories have been
+                    dropped from the default value of the
+                    <link linkend='var-FILESPATH'><filename>FILESPATH</filename></link>
+                    variable, which is used as the search path for finding files
+                    referred to in
+                    <link linkend='var-SRC_URI'><filename>SRC_URI</filename></link>.
+                    If you have a recipe that relied upon these directories,
+                    which would be unusual, then you will need to add the
+                    appropriate paths within the recipe or, alternatively,
+                    rearrange the files.
+                    The most common locations are still covered by
+                    <filename>${BP}</filename>, <filename>${BPN}</filename>,
+                    and "files", which all remain in the default value of
+                    <link linkend='var-FILESPATH'><filename>FILESPATH</filename></link>.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-target-package-management-with-rpm'>
+        <title>Target Package Management with RPM</title>
+
+        <para>
+            If runtime package management is enabled and the RPM backend
+            is selected, Smart is now installed for package download, dependency
+            resolution, and upgrades instead of Zypper.
+            For more information on how to use Smart, run the following command
+            on the target:
+            <literallayout class='monospaced'>
+     smart --help
+            </literallayout>
+        </para>
+    </section>
+
+    <section id='migration-1.4-recipes-moved'>
+        <title>Recipes Moved</title>
+
+        <para>
+            The following recipes were moved from their previous locations
+            because they are no longer used by anything in
+            the OpenEmbedded-Core:
+            <itemizedlist>
+                <listitem><para><emphasis><filename>clutter-box2d</filename>:</emphasis>
+                    Now resides in the <filename>meta-oe</filename> layer.
+                    </para></listitem>
+                <listitem><para><emphasis><filename>evolution-data-server</filename>:</emphasis>
+                    Now resides in the <filename>meta-gnome</filename> layer.
+                    </para></listitem>
+                <listitem><para><emphasis><filename>gthumb</filename>:</emphasis>
+                    Now resides in the <filename>meta-gnome</filename> layer.
+                    </para></listitem>
+                <listitem><para><emphasis><filename>gtkhtml2</filename>:</emphasis>
+                    Now resides in the <filename>meta-oe</filename> layer.
+                    </para></listitem>
+                <listitem><para><emphasis><filename>gupnp</filename>:</emphasis>
+                    Now resides in the <filename>meta-multimedia</filename> layer.
+                    </para></listitem>
+                <listitem><para><emphasis><filename>gypsy</filename>:</emphasis>
+                    Now resides in the <filename>meta-oe</filename> layer.
+                    </para></listitem>
+                <listitem><para><emphasis><filename>libcanberra</filename>:</emphasis>
+                    Now resides in the <filename>meta-gnome</filename> layer.
+                    </para></listitem>
+                <listitem><para><emphasis><filename>libgdata</filename>:</emphasis>
+                    Now resides in the <filename>meta-gnome</filename> layer.
+                    </para></listitem>
+                <listitem><para><emphasis><filename>libmusicbrainz</filename>:</emphasis>
+                    Now resides in the <filename>meta-multimedia</filename> layer.
+                    </para></listitem>
+                <listitem><para><emphasis><filename>metacity</filename>:</emphasis>
+                    Now resides in the <filename>meta-gnome</filename> layer.
+                    </para></listitem>
+                <listitem><para><emphasis><filename>polkit</filename>:</emphasis>
+                    Now resides in the <filename>meta-oe</filename> layer.
+                    </para></listitem>
+                <listitem><para><emphasis><filename>zeroconf</filename>:</emphasis>
+                    Now resides in the <filename>meta-networking</filename> layer.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-1.4-removals-and-renames'>
+        <title>Removals and Renames</title>
+
+        <para>
+            The following list shows what has been removed or renamed:
+            <itemizedlist>
+                <listitem><para><emphasis><filename>evieext</filename>:</emphasis>
+                    Removed because it has been removed from
+                    <filename>xserver</filename> since 2008.
+                    </para></listitem>
+                <listitem><para><emphasis>Gtk+ DirectFB:</emphasis>
+                    Removed support because upstream Gtk+ no longer supports it
+                    as of version 2.18.
+                    </para></listitem>
+                <listitem><para><emphasis><filename>libxfontcache / xfontcacheproto</filename>:</emphasis>
+                    Removed because they were removed from the Xorg server in 2008.
+                    </para></listitem>
+                <listitem><para><emphasis><filename>libxp / libxprintapputil / libxprintutil / printproto</filename>:</emphasis>
+                    Removed because the XPrint server was removed from
+                    Xorg in 2008.
+                    </para></listitem>
+                <listitem><para><emphasis><filename>libxtrap / xtrapproto</filename>:</emphasis>
+                    Removed because their functionality was broken upstream.
+                    </para></listitem>
+                <listitem><para><emphasis>linux-yocto 3.0 kernel:</emphasis>
+                    Removed with linux-yocto 3.8 kernel being added.
+                    The linux-yocto 3.2 and linux-yocto 3.4 kernels remain
+                    as part of the release.
+                    </para></listitem>
+                <listitem><para><emphasis><filename>lsbsetup</filename>:</emphasis>
+                    Removed with functionality now provided by
+                    <filename>lsbtest</filename>.
+                    </para></listitem>
+                <listitem><para><emphasis><filename>matchbox-stroke</filename>:</emphasis>
+                    Removed because it was never more than a proof-of-concept.
+                    </para></listitem>
+                <listitem><para><emphasis><filename>matchbox-wm-2 / matchbox-theme-sato-2</filename>:</emphasis>
+                    Removed because they are not maintained.
+                    However, <filename>matchbox-wm</filename> and
+                    <filename>matchbox-theme-sato</filename> are still
+                    provided.
+                    </para></listitem>
+                <listitem><para><emphasis><filename>mesa-dri</filename>:</emphasis>
+                    Renamed to <filename>mesa</filename>.
+                    </para></listitem>
+                <listitem><para><emphasis><filename>mesa-xlib</filename>:</emphasis>
+                    Removed because it was no longer useful.
+                    </para></listitem>
+                <listitem><para><emphasis><filename>mutter</filename>:</emphasis>
+                    Removed because nothing ever uses it and the recipe is
+                    very old.
+                    </para></listitem>
+                <listitem><para><emphasis><filename>orinoco-conf</filename>:</emphasis>
+                    Removed because it has become obsolete.
+                    </para></listitem>
+                <listitem><para><emphasis><filename>update-modules</filename>:</emphasis>
+                    Removed because it is no longer used.
+                    The kernel module <filename>postinstall</filename> and
+                    <filename>postrm</filename> scripts can now do the same
+                    task without the use of this script.
+                    </para></listitem>
+                <listitem><para><emphasis><filename>web</filename>:</emphasis>
+                    Removed because it is not maintained.  Superseded by
+                    <filename>web-webkit</filename>.
+                    </para></listitem>
+                <listitem><para><emphasis><filename>xf86bigfontproto</filename>:</emphasis>
+                    Removed because upstream it has been disabled by default
+                    since 2007.
+                    Nothing uses <filename>xf86bigfontproto</filename>.
+                    </para></listitem>
+                <listitem><para><emphasis><filename>xf86rushproto</filename>:</emphasis>
+                    Removed because its dependency in
+                    <filename>xserver</filename> was spurious and it was
+                    removed in 2005.
+                    </para></listitem>
+                <listitem><para><emphasis><filename>zypper / libzypp / sat-solver</filename>:</emphasis>
+                    Removed and been functionally replaced with Smart
+                    (<filename>python-smartpm</filename>) when RPM packaging
+                    is used and package management is enabled on the target.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+</section>
+
+<section id='moving-to-the-yocto-project-1.5-release'>
+    <title>Moving to the Yocto Project 1.5 Release</title>
+
+    <para>
+        This section provides migration information for moving to the
+        Yocto Project 1.5 Release from the prior release.
+    </para>
+
+    <section id='migration-1.5-host-dependency-changes'>
+        <title>Host Dependency Changes</title>
+
+        <para>
+            The OpenEmbedded build system now has some additional requirements
+            on the host system:
+            <itemizedlist>
+                <listitem><para>Python 2.7.3+</para></listitem>
+                <listitem><para>Tar 1.24+</para></listitem>
+                <listitem><para>Git 1.7.8+</para></listitem>
+                <listitem><para>Patched version of Make if you are using
+                    3.82.
+                    Most distributions that provide Make 3.82 use the patched
+                    version.</para></listitem>
+            </itemizedlist>
+            If the Linux distribution you are using on your build host
+            does not provide packages for these, you can install and use
+            the Buildtools tarball, which provides an SDK-like environment
+            containing them.
+        </para>
+
+        <para>
+            For more information on this requirement, see the
+            "<link linkend='required-git-tar-python-and-gcc-versions'>Required Git, tar, Python and gcc Versions</link>"
+            section.
+        </para>
+    </section>
+
+    <section id='migration-1.5-atom-pc-bsp'>
+        <title><filename>atom-pc</filename> Board Support Package (BSP)</title>
+
+        <para>
+            The <filename>atom-pc</filename> hardware reference BSP has been
+            replaced by a <filename>genericx86</filename> BSP.
+            This BSP is not necessarily guaranteed to work on all x86
+            hardware, but it will run on a wider range of systems than the
+            <filename>atom-pc</filename> did.
+            <note>
+                Additionally, a <filename>genericx86-64</filename> BSP has
+                been added for 64-bit Atom systems.
+            </note>
+        </para>
+    </section>
+
+    <section id='migration-1.5-bitbake'>
+        <title>BitBake</title>
+
+        <para>
+            The following changes have been made that relate to BitBake:
+            <itemizedlist>
+                <listitem><para>
+                    BitBake now supports a <filename>_remove</filename>
+                    operator.
+                    The addition of this operator means you will have to
+                    rename any items in recipe space (functions, variables)
+                    whose names currently contain
+                    <filename>_remove_</filename> or end with
+                    <filename>_remove</filename> to avoid unexpected behavior.
+                    </para></listitem>
+                <listitem><para>
+                    BitBake's global method pool has been removed.
+                    This method is not particularly useful and led to clashes
+                    between recipes containing functions that had the
+                    same name.</para></listitem>
+                <listitem><para>
+                    The "none" server backend has been removed.
+                    The "process" server backend has been serving well as the
+                    default for a long time now.</para></listitem>
+                <listitem><para>
+                    The <filename>bitbake-runtask</filename> script has been
+                    removed.</para></listitem>
+                <listitem><para>
+                    <filename>${</filename><link linkend='var-P'><filename>P</filename></link><filename>}</filename>
+                    and
+                    <filename>${</filename><link linkend='var-PF'><filename>PF</filename></link><filename>}</filename>
+                    are no longer added to
+                    <link linkend='var-PROVIDES'><filename>PROVIDES</filename></link>
+                    by default in <filename>bitbake.conf</filename>.
+                    These version-specific <filename>PROVIDES</filename>
+                    items were seldom used.
+                    Attempting to use them could result in two versions being
+                    built simultaneously rather than just one version due to
+                    the way BitBake resolves dependencies.</para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-1.5-qa-warnings'>
+        <title>QA Warnings</title>
+
+        <para>
+            The following changes have been made to the package QA checks:
+            <itemizedlist>
+                <listitem><para>
+                    If you have customized
+                    <link linkend='var-ERROR_QA'><filename>ERROR_QA</filename></link>
+                    or <link linkend='var-WARN_QA'><filename>WARN_QA</filename></link>
+                    values in your configuration, check that they contain all of
+                    the issues that you wish to be reported.
+                    Previous Yocto Project versions contained a bug that meant
+                    that any item not mentioned in <filename>ERROR_QA</filename>
+                    or <filename>WARN_QA</filename> would be treated as a
+                    warning.
+                    Consequently, several important items were not already in
+                    the default value of <filename>WARN_QA</filename>.
+                    All of the possible QA checks are now documented in the
+                    "<link linkend='ref-classes-insane'><filename>insane.bbclass</filename></link>"
+                    section.</para></listitem>
+                <listitem><para>
+                    An additional QA check has been added to check if
+                    <filename>/usr/share/info/dir</filename> is being installed.
+                    Your recipe should delete this file within
+                    <link linkend='ref-tasks-install'><filename>do_install</filename></link>
+                    if "make install" is installing it.
+                    </para></listitem>
+                <listitem><para>
+                    If you are using the buildhistory class, the check for the
+                    package version going backwards is now controlled using a
+                    standard QA check.
+                    Thus, if you have customized your
+                    <filename>ERROR_QA</filename> or
+                    <filename>WARN_QA</filename> values and still wish to have
+                    this check performed, you should add
+                    "version-going-backwards" to your value for one or the
+                    other variables depending on how you wish it to be handled.
+                    See the documented QA checks in the
+                    "<link linkend='ref-classes-insane'><filename>insane.bbclass</filename></link>"
+                    section.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-1.5-directory-layout-changes'>
+        <title>Directory Layout Changes</title>
+
+        <para>
+            The following directory changes exist:
+            <itemizedlist>
+                <listitem><para>
+                    Output SDK installer files are now named to include the
+                    image name and tuning architecture through the
+                    <link linkend='var-SDK_NAME'><filename>SDK_NAME</filename></link>
+                    variable.</para></listitem>
+                <listitem><para>
+                    Images and related files are now installed into a directory
+                    that is specific to the machine, instead of a parent
+                    directory containing output files for multiple machines.
+                    The
+                    <link linkend='var-DEPLOY_DIR_IMAGE'><filename>DEPLOY_DIR_IMAGE</filename></link>
+                    variable continues to point to the directory containing
+                    images for the current
+                    <link linkend='var-MACHINE'><filename>MACHINE</filename></link>
+                    and should be used anywhere there is a need to refer to
+                    this directory.
+                    The <filename>runqemu</filename> script now uses this
+                    variable to find images and kernel binaries and will use
+                    BitBake to determine the directory.
+                    Alternatively, you can set the
+                    <filename>DEPLOY_DIR_IMAGE</filename> variable in the
+                    external environment.</para></listitem>
+                <listitem><para>
+                    When buildhistory is enabled, its output is now written
+                    under the
+                    <link linkend='build-directory'>Build Directory</link>
+                    rather than
+                    <link linkend='var-TMPDIR'><filename>TMPDIR</filename></link>.
+                    Doing so makes it easier to delete
+                    <filename>TMPDIR</filename> and preserve the build history.
+                    Additionally, data for produced SDKs is now split by
+                    <link linkend='var-IMAGE_NAME'><filename>IMAGE_NAME</filename></link>.
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>pkgdata</filename> directory produced as
+                    part of the packaging process has been collapsed into a
+                    single machine-specific directory.
+                    This directory is located under
+                    <filename>sysroots</filename> and uses a machine-specific
+                    name (i.e.
+                    <filename>tmp/sysroots/<replaceable>machine</replaceable>/pkgdata</filename>).
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-1.5-shortened-git-srcrev-values'>
+        <title>Shortened Git <filename>SRCREV</filename> Values</title>
+
+        <para>
+            BitBake will now shorten revisions from Git repositories from the
+            normal 40 characters down to 10 characters within
+            <link linkend='var-SRCPV'><filename>SRCPV</filename></link>
+            for improved usability in path and file names.
+            This change should be safe within contexts where these revisions
+            are used because the chances of spatially close collisions
+            is very low.
+            Distant collisions are not a major issue in the way
+            the values are used.
+        </para>
+    </section>
+
+    <section id='migration-1.5-image-features'>
+        <title><filename>IMAGE_FEATURES</filename></title>
+
+        <para>
+            The following changes have been made that relate to
+            <link linkend='var-IMAGE_FEATURES'><filename>IMAGE_FEATURES</filename></link>:
+            <itemizedlist>
+                <listitem><para>
+                    The value of <filename>IMAGE_FEATURES</filename> is now
+                    validated to ensure invalid feature items are not added.
+                    Some users mistakenly add package names to this variable
+                    instead of using
+                    <link linkend='var-IMAGE_INSTALL'><filename>IMAGE_INSTALL</filename></link>
+                    in order to have the package added to the image, which does
+                    not work.
+                    This change is intended to catch those kinds of situations.
+                    Valid <filename>IMAGE_FEATURES</filename> are drawn from
+                    <filename>PACKAGE_GROUP</filename> definitions,
+                    <link linkend='var-COMPLEMENTARY_GLOB'><filename>COMPLEMENTARY_GLOB</filename></link>
+                    and a new "validitems" varflag on
+                    <filename>IMAGE_FEATURES</filename>.
+                    The "validitems" varflag change allows additional features
+                    to be added if they are not provided using the previous
+                    two mechanisms.
+                    </para></listitem>
+                <listitem><para>
+                    The previously deprecated "apps-console-core"
+                    <filename>IMAGE_FEATURES</filename> item is no longer
+                    supported.
+                    Add "splash" to <filename>IMAGE_FEATURES</filename> if you
+                    wish to have the splash screen enabled, since this is
+                    all that apps-console-core was doing.</para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-1.5-run'>
+        <title><filename>/run</filename></title>
+
+        <para>
+            The <filename>/run</filename> directory from the Filesystem
+            Hierarchy Standard 3.0 has been introduced.
+            You can find some of the implications for this change
+            <ulink url='http://cgit.openembedded.org/openembedded-core/commit/?id=0e326280a15b0f2c4ef2ef4ec441f63f55b75873'>here</ulink>.
+            The change also means that recipes that install files to
+            <filename>/var/run</filename> must be changed.
+            You can find a guide on how to make these changes
+            <ulink url='http://permalink.gmane.org/gmane.comp.handhelds.openembedded/58530'>here</ulink>.
+        </para>
+    </section>
+
+    <section id='migration-1.5-removal-of-package-manager-database-within-image-recipes'>
+        <title>Removal of Package Manager Database Within Image Recipes</title>
+
+        <para>
+            The image <filename>core-image-minimal</filename> no longer adds
+            <filename>remove_packaging_data_files</filename> to
+            <link linkend='var-ROOTFS_POSTPROCESS_COMMAND'><filename>ROOTFS_POSTPROCESS_COMMAND</filename></link>.
+            This addition is now handled automatically when "package-management"
+            is not in
+            <link linkend='var-IMAGE_FEATURES'><filename>IMAGE_FEATURES</filename></link>.
+            If you have custom image recipes that make this addition,
+            you should remove the lines, as they are not needed and might
+            interfere with correct operation of postinstall scripts.
+        </para>
+    </section>
+
+    <section id='migration-1.5-images-now-rebuild-only-on-changes-instead-of-every-time'>
+        <title>Images Now Rebuild Only on Changes Instead of Every Time</title>
+
+        <para>
+            The
+            <link linkend='ref-tasks-rootfs'><filename>do_rootfs</filename></link>
+            and other related image
+            construction tasks are no longer marked as "nostamp".
+            Consequently, they will only be re-executed when their inputs have
+            changed.
+            Previous versions of the OpenEmbedded build system always rebuilt
+            the image when requested rather when necessary.
+        </para>
+    </section>
+
+    <section id='migration-1.5-task-recipes'>
+        <title>Task Recipes</title>
+
+        <para>
+            The previously deprecated <filename>task.bbclass</filename> has
+            now been dropped.
+            For recipes that previously inherited from this class, you should
+            rename them from <filename>task-*</filename> to
+            <filename>packagegroup-*</filename> and inherit packagegroup
+            instead.
+        </para>
+
+        <para>
+            For more information, see the
+            "<link linkend='ref-classes-packagegroup'><filename>packagegroup.bbclass</filename></link>"
+            section.
+        </para>
+    </section>
+
+    <section id='migration-1.5-busybox'>
+        <title>BusyBox</title>
+
+        <para>
+            By default, we now split BusyBox into two binaries:
+            one that is suid root for those components that need it, and
+            another for the rest of the components.
+            Splitting BusyBox allows for optimization that eliminates the
+            <filename>tinylogin</filename> recipe as recommended by upstream.
+            You can disable this split by setting
+            <link linkend='var-BUSYBOX_SPLIT_SUID'><filename>BUSYBOX_SPLIT_SUID</filename></link>
+            to "0".
+        </para>
+    </section>
+
+    <section id='migration-1.5-automated-image-testing'>
+        <title>Automated Image Testing</title>
+
+        <para>
+            A new automated image testing framework has been added
+            through the
+            <link linkend='ref-classes-testimage*'><filename>testimage.bbclass</filename></link>
+            class.
+            This framework replaces the older
+            <filename>imagetest-qemu</filename> framework.
+        </para>
+
+        <para>
+            You can learn more about performing automated image tests in the
+            "<ulink url='&YOCTO_DOCS_DEV_URL;#performing-automated-runtime-testing'>Performing Automated Runtime Testing</ulink>"
+            section in the Yocto Project Development Tasks Manual.
+        </para>
+    </section>
+
+    <section id='migration-1.5-build-history'>
+        <title>Build History</title>
+
+        <para>
+            Following are changes to Build History:
+            <itemizedlist>
+                <listitem><para>
+                     Installed package sizes:
+                     <filename>installed-package-sizes.txt</filename> for an
+                     image now records the size of the files installed by each
+                     package instead of the size of each compressed package
+                     archive file.</para></listitem>
+                <listitem><para>
+                    The dependency graphs (<filename>depends*.dot</filename>)
+                    now use the actual package names instead of replacing
+                    dashes, dots and plus signs with underscores.
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>buildhistory-diff</filename> and
+                    <filename>buildhistory-collect-srcrevs</filename>
+                    utilities have improved command-line handling.
+                    Use the <filename>--help</filename> option for
+                    each utility for more information on the new syntax.
+                    </para></listitem>
+            </itemizedlist>
+            For more information on Build History, see the
+            "<ulink url='&YOCTO_DOCS_DEV_URL;#maintaining-build-output-quality'>Maintaining Build Output Quality</ulink>"
+            section in the Yocto Project Development Tasks Manual.
+        </para>
+    </section>
+
+    <section id='migration-1.5-udev'>
+        <title><filename>udev</filename></title>
+
+        <para>
+            Following are changes to <filename>udev</filename>:
+            <itemizedlist>
+                <listitem><para>
+                    <filename>udev</filename> no longer brings in
+                    <filename>udev-extraconf</filename> automatically
+                    through
+                    <link linkend='var-RRECOMMENDS'><filename>RRECOMMENDS</filename></link>,
+                    since this was originally intended to be optional.
+                    If you need the extra rules, then add
+                    <filename>udev-extraconf</filename> to your image.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>udev</filename> no longer brings in
+                    <filename>pciutils-ids</filename> or
+                    <filename>usbutils-ids</filename> through
+                    <filename>RRECOMMENDS</filename>.
+                    These are not needed by <filename>udev</filename> itself
+                    and removing them saves around 350KB.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-1.5-removed-renamed-recipes'>
+        <title>Removed and Renamed Recipes</title>
+
+        <itemizedlist>
+            <listitem><para>
+                The <filename>linux-yocto</filename> 3.2 kernel has been
+                removed.</para></listitem>
+            <listitem><para>
+                <filename>libtool-nativesdk</filename> has been renamed to
+                <filename>nativesdk-libtool</filename>.</para></listitem>
+            <listitem><para>
+                <filename>tinylogin</filename> has been removed.
+                It has been replaced by a suid portion of Busybox.
+                See the
+                "<link linkend='migration-1.5-busybox'>BusyBox</link>" section
+                for more information.</para></listitem>
+            <listitem><para>
+                <filename>external-python-tarball</filename> has been renamed
+                to <filename>buildtools-tarball</filename>.
+                </para></listitem>
+            <listitem><para>
+                <filename>web-webkit</filename> has been removed.
+                It has been functionally replaced by
+                <filename>midori</filename>.</para></listitem>
+            <listitem><para>
+                <filename>imake</filename> has been removed.
+                It is no longer needed by any other recipe.
+                </para></listitem>
+            <listitem><para>
+                <filename>transfig-native</filename> has been removed.
+                It is no longer needed by any other recipe.
+                </para></listitem>
+            <listitem><para>
+                <filename>anjuta-remote-run</filename> has been removed.
+                Anjuta IDE integration has not been officially supported for
+                several releases.</para></listitem>
+        </itemizedlist>
+    </section>
+
+    <section id='migration-1.5-other-changes'>
+        <title>Other Changes</title>
+
+        <para>
+            Following is a list of short entries describing other changes:
+            <itemizedlist>
+                <listitem><para>
+                    <filename>run-postinsts</filename>: Make this generic.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>base-files</filename>: Remove the unnecessary
+                    <filename>media/</filename><replaceable>xxx</replaceable> directories.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>alsa-state</filename>: Provide an empty
+                    <filename>asound.conf</filename> by default.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>classes/image</filename>: Ensure
+                    <link linkend='var-BAD_RECOMMENDATIONS'><filename>BAD_RECOMMENDATIONS</filename></link>
+                    supports pre-renamed package names.</para></listitem>
+                <listitem><para>
+                    <filename>classes/rootfs_rpm</filename>: Implement
+                    <filename>BAD_RECOMMENDATIONS</filename> for RPM.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>systemd</filename>: Remove
+                    <filename>systemd_unitdir</filename> if
+                    <filename>systemd</filename> is not in
+                    <link linkend='var-DISTRO_FEATURES'><filename>DISTRO_FEATURES</filename></link>.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>systemd</filename>: Remove
+                    <filename>init.d</filename> dir if
+                    <filename>systemd</filename> unit file is present and
+                    <filename>sysvinit</filename> is not a distro feature.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>libpam</filename>: Deny all services for the
+                    <filename>OTHER</filename> entries.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>image.bbclass</filename>: Move
+                    <filename>runtime_mapping_rename</filename> to avoid
+                    conflict with <filename>multilib</filename>.
+                    See
+                    <ulink url='https://bugzilla.yoctoproject.org/show_bug.cgi?id=4993'><filename>YOCTO #4993</filename></ulink>
+                    in Bugzilla for more information.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>linux-dtb</filename>: Use kernel build system
+                    to generate the <filename>dtb</filename> files.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>kern-tools</filename>: Switch from guilt to
+                    new <filename>kgit-s2q</filename> tool.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+</section>
+
+<section id='moving-to-the-yocto-project-1.6-release'>
+    <title>Moving to the Yocto Project 1.6 Release</title>
+
+    <para>
+        This section provides migration information for moving to the
+        Yocto Project 1.6 Release from the prior release.
+    </para>
+
+
+    <section id='migration-1.6-archiver-class'>
+        <title><filename>archiver</filename> Class</title>
+
+        <para>
+            The
+            <link linkend='ref-classes-archiver'><filename>archiver</filename></link>
+            class has been rewritten and its configuration has been simplified.
+            For more details on the source archiver, see the
+            "<ulink url='&YOCTO_DOCS_DEV_URL;#maintaining-open-source-license-compliance-during-your-products-lifecycle'>Maintaining Open Source License Compliance During Your Product's Lifecycle</ulink>"
+            section in the Yocto Project Development Tasks Manual.
+        </para>
+    </section>
+
+    <section id='migration-1.6-packaging-changes'>
+        <title>Packaging Changes</title>
+
+        <para>
+            The following packaging changes have been made:
+            <itemizedlist>
+                <listitem><para>
+                    The <filename>binutils</filename> recipe no longer produces
+                    a <filename>binutils-symlinks</filename> package.
+                    <filename>update-alternatives</filename> is now used to
+                    handle the preferred <filename>binutils</filename>
+                    variant on the target instead.
+                    </para></listitem>
+                <listitem><para>
+                    The tc (traffic control) utilities have been split out of
+                    the main <filename>iproute2</filename> package and put
+                    into the <filename>iproute2-tc</filename> package.
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>gtk-engines</filename> schemas have been
+                    moved to a dedicated
+                    <filename>gtk-engines-schemas</filename> package.
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>armv7a</filename> with thumb package
+                    architecture suffix has changed.
+                    The suffix for these packages with the thumb
+                    optimization enabled is "t2" as it should be.
+                    Use of this suffix was not the case in the 1.5 release.
+                    Architecture names will change within package feeds as a
+                    result.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-1.6-bitbake'>
+        <title>BitBake</title>
+
+        <para>
+            The following changes have been made to
+            <link linkend='bitbake-term'>BitBake</link>.
+        </para>
+
+        <section id='migration-1.6-matching-branch-requirement-for-git-fetching'>
+            <title>Matching Branch Requirement for Git Fetching</title>
+
+            <para>
+                When fetching source from a Git repository using
+                <link linkend='var-SRC_URI'><filename>SRC_URI</filename></link>,
+                BitBake will now validate the
+                <link linkend='var-SRCREV'><filename>SRCREV</filename></link>
+                value against the branch.
+                You can specify the branch using the following form:
+                <literallayout class='monospaced'>
+     SRC_URI = "git://server.name/repository;branch=<replaceable>branchname</replaceable>"
+                </literallayout>
+                If you do not specify a branch, BitBake looks
+                in the default "master" branch.
+            </para>
+
+            <para>
+                Alternatively, if you need to bypass this check (e.g.
+                if you are fetching a revision corresponding to a tag that
+                is not on any branch), you can add ";nobranch=1" to
+                the end of the URL within <filename>SRC_URI</filename>.
+            </para>
+        </section>
+
+        <section id='migration-1.6-bitbake-deps'>
+            <title>Python Definition substitutions</title>
+
+            <para>
+                BitBake had some previously deprecated Python definitions
+                within its <filename>bb</filename> module removed.
+                You should use their sub-module counterparts instead:
+                <itemizedlist>
+                    <listitem><para><filename>bb.MalformedUrl</filename>:
+                        Use <filename>bb.fetch.MalformedUrl</filename>.
+                        </para></listitem>
+                    <listitem><para><filename>bb.encodeurl</filename>:
+                        Use <filename>bb.fetch.encodeurl</filename>.
+                        </para></listitem>
+                    <listitem><para><filename>bb.decodeurl</filename>:
+                        Use <filename>bb.fetch.decodeurl</filename>
+                        </para></listitem>
+                    <listitem><para><filename>bb.mkdirhier</filename>:
+                        Use <filename>bb.utils.mkdirhier</filename>.
+                        </para></listitem>
+                    <listitem><para><filename>bb.movefile</filename>:
+                        Use <filename>bb.utils.movefile</filename>.
+                        </para></listitem>
+                    <listitem><para><filename>bb.copyfile</filename>:
+                        Use <filename>bb.utils.copyfile</filename>.
+                        </para></listitem>
+                    <listitem><para><filename>bb.which</filename>:
+                        Use <filename>bb.utils.which</filename>.
+                        </para></listitem>
+                    <listitem><para><filename>bb.vercmp_string</filename>:
+                        Use <filename>bb.utils.vercmp_string</filename>.
+                        </para></listitem>
+                    <listitem><para><filename>bb.vercmp</filename>:
+                        Use <filename>bb.utils.vercmp</filename>.
+                        </para></listitem>
+                </itemizedlist>
+            </para>
+        </section>
+
+        <section id='migration-1.6-bitbake-fetcher'>
+            <title>SVK Fetcher</title>
+
+            <para>
+                The SVK fetcher has been removed from BitBake.
+            </para>
+        </section>
+
+        <section id='migration-1.6-bitbake-console-output'>
+            <title>Console Output Error Redirection</title>
+
+            <para>
+                The BitBake console UI will now output errors to
+                <filename>stderr</filename> instead of
+                <filename>stdout</filename>.
+                Consequently, if you are piping or redirecting the output of
+                <filename>bitbake</filename> to somewhere else, and you wish
+                to retain the errors, you will need to add
+                <filename>2>&amp;1</filename> (or something similar) to the
+                end of your <filename>bitbake</filename> command line.
+            </para>
+        </section>
+
+        <section id='migration-1.6-task-taskname-overrides'>
+            <title><filename>task-</filename><replaceable>taskname</replaceable> Overrides</title>
+
+            <para>
+                <filename>task-</filename><replaceable>taskname</replaceable> overrides have been
+                adjusted so that tasks whose names contain underscores have the
+                underscores replaced by hyphens for the override so that they
+                now function properly.
+                For example, the task override for
+                <link linkend='ref-tasks-populate_sdk'><filename>do_populate_sdk</filename></link>
+                is <filename>task-populate-sdk</filename>.
+            </para>
+        </section>
+    </section>
+
+    <section id='migration-1.6-variable-changes'>
+        <title>Changes to Variables</title>
+
+        <para>
+            The following variables have changed.
+            For information on the OpenEmbedded build system variables, see the
+            "<link linkend='ref-variables-glos'>Variables Glossary</link>" Chapter.
+        </para>
+
+        <section id='migration-1.6-variable-changes-TMPDIR'>
+            <title><filename>TMPDIR</filename></title>
+
+            <para>
+                <link linkend='var-TMPDIR'><filename>TMPDIR</filename></link>
+                can no longer be on an NFS mount.
+                NFS does not offer full POSIX locking and inode consistency
+                and can cause unexpected issues if used to store
+                <filename>TMPDIR</filename>.
+            </para>
+
+            <para>
+                The check for this occurs on startup.
+                If <filename>TMPDIR</filename> is detected on an NFS mount,
+                an error occurs.
+            </para>
+        </section>
+
+        <section id='migration-1.6-variable-changes-PRINC'>
+            <title><filename>PRINC</filename></title>
+
+            <para>
+                The <filename>PRINC</filename>
+                variable has been deprecated and triggers a warning if
+                detected during a build.
+                For
+                <link linkend='var-PR'><filename>PR</filename></link>
+                increments on changes, use the PR service instead.
+                You can find out more about this service in the
+                "<ulink url='&YOCTO_DOCS_DEV_URL;#working-with-a-pr-service'>Working With a PR Service</ulink>"
+                section in the Yocto Project Development Tasks Manual.
+            </para>
+        </section>
+
+        <section id='migration-1.6-variable-changes-IMAGE_TYPES'>
+            <title><filename>IMAGE_TYPES</filename></title>
+
+            <para>
+                The "sum.jffs2" option for
+                <link linkend='var-IMAGE_TYPES'><filename>IMAGE_TYPES</filename></link>
+                has been replaced by the "jffs2.sum" option, which fits the
+                processing order.
+            </para>
+        </section>
+
+        <section id='migration-1.6-variable-changes-COPY_LIC_MANIFEST'>
+            <title><filename>COPY_LIC_MANIFEST</filename></title>
+
+            <para>
+                The
+                <link linkend='var-COPY_LIC_MANIFEST'><filename>COPY_LIC_MANIFEST</filename></link>
+                variable must
+                now be set to "1" rather than any value in order to enable
+                it.
+            </para>
+        </section>
+
+        <section id='migration-1.6-variable-changes-COPY_LIC_DIRS'>
+            <title><filename>COPY_LIC_DIRS</filename></title>
+
+            <para>
+                The
+                <link linkend='var-COPY_LIC_DIRS'><filename>COPY_LIC_DIRS</filename></link>
+                variable must
+                now be set to "1" rather than any value in order to enable
+                it.
+            </para>
+        </section>
+
+        <section id='migration-1.6-variable-changes-PACKAGE_GROUP'>
+            <title><filename>PACKAGE_GROUP</filename></title>
+
+            <para>
+                The
+                <filename>PACKAGE_GROUP</filename> variable has been renamed to
+                <link linkend='var-FEATURE_PACKAGES'><filename>FEATURE_PACKAGES</filename></link>
+                to more accurately reflect its purpose.
+                You can still use <filename>PACKAGE_GROUP</filename> but
+                the OpenEmbedded build system produces a warning message when
+                it encounters the variable.
+            </para>
+        </section>
+
+        <section id='migration-1.6-variable-changes-variable-entry-behavior'>
+            <title>Preprocess and Post Process Command Variable Behavior</title>
+
+            <para>
+                The following variables now expect a semicolon separated
+                list of functions to call and not arbitrary shell commands:
+                <literallayout class='monospaced'>
+     <link linkend='var-ROOTFS_PREPROCESS_COMMAND'>ROOTFS_PREPROCESS_COMMAND</link>
+     <link linkend='var-ROOTFS_POSTPROCESS_COMMAND'>ROOTFS_POSTPROCESS_COMMAND</link>
+     <link linkend='var-SDK_POSTPROCESS_COMMAND'>SDK_POSTPROCESS_COMMAND</link>
+     <link linkend='var-POPULATE_SDK_POST_TARGET_COMMAND'>POPULATE_SDK_POST_TARGET_COMMAND</link>
+     <link linkend='var-POPULATE_SDK_POST_HOST_COMMAND'>POPULATE_SDK_POST_HOST_COMMAND</link>
+     <link linkend='var-IMAGE_POSTPROCESS_COMMAND'>IMAGE_POSTPROCESS_COMMAND</link>
+     <link linkend='var-IMAGE_PREPROCESS_COMMAND'>IMAGE_PREPROCESS_COMMAND</link>
+     <link linkend='var-ROOTFS_POSTUNINSTALL_COMMAND'>ROOTFS_POSTUNINSTALL_COMMAND</link>
+     <link linkend='var-ROOTFS_POSTINSTALL_COMMAND'>ROOTFS_POSTINSTALL_COMMAND</link>
+                </literallayout>
+                For migration purposes, you can simply wrap shell commands in
+                a shell function and then call the function.
+                Here is an example:
+                <literallayout class='monospaced'>
+     my_postprocess_function() {
+        echo "hello" > ${IMAGE_ROOTFS}/hello.txt
+     }
+     ROOTFS_POSTPROCESS_COMMAND += "my_postprocess_function; "
+                </literallayout>
+            </para>
+        </section>
+    </section>
+
+    <section id='migration-1.6-package-test-ptest'>
+        <title>Package Test (ptest)</title>
+
+        <para>
+            Package Tests (ptest) are built but not installed by default.
+            For information on using Package Tests, see the
+            "<ulink url='&YOCTO_DOCS_DEV_URL;#testing-packages-with-ptest'>Testing Packages with ptest</ulink>"
+            section in the Yocto Project Development Tasks Manual.
+            For information on the <filename>ptest</filename> class, see the
+            "<link linkend='ref-classes-ptest'><filename>ptest.bbclass</filename></link>"
+            section.
+        </para>
+    </section>
+
+    <section id='migration-1.6-build-changes'>
+        <title>Build Changes</title>
+
+        <para>
+            Separate build and source directories have been enabled
+            by default for selected recipes where it is known to work
+            (a whitelist) and for all recipes that inherit the
+            <link linkend='ref-classes-cmake'><filename>cmake</filename></link>
+            class.
+            In future releases the
+            <link linkend='ref-classes-autotools'><filename>autotools</filename></link>
+            class will enable a separate build directory by default as
+            well.
+            Recipes building Autotools-based
+            software that fails to build with a separate build directory
+            should be changed to inherit from the
+            <link linkend='ref-classes-autotools'><filename>autotools-brokensep</filename></link>
+            class instead of the <filename>autotools</filename> or
+            <filename>autotools_stage</filename>classes.
+        </para>
+    </section>
+
+    <section id='migration-1.6-building-qemu-native'>
+        <title><filename>qemu-native</filename></title>
+
+        <para>
+            <filename>qemu-native</filename> now builds without
+            SDL-based graphical output support by default.
+            The following additional lines are needed in your
+            <filename>local.conf</filename> to enable it:
+            <literallayout class='monospaced'>
+     PACKAGECONFIG_pn-qemu-native = "sdl"
+     ASSUME_PROVIDED += "libsdl-native"
+            </literallayout>
+            <note>
+                The default <filename>local.conf</filename>
+                contains these statements.
+                Consequently, if you are building a headless system and using
+                a default <filename>local.conf</filename> file, you will need
+                comment these two lines out.
+            </note>
+        </para>
+    </section>
+
+    <section id='migration-1.6-core-image-basic'>
+        <title><filename>core-image-basic</filename></title>
+
+        <para>
+            <filename>core-image-basic</filename> has been renamed to
+            <filename>core-image-full-cmdline</filename>.
+        </para>
+
+        <para>
+            In addition to <filename>core-image-basic</filename> being renamed,
+            <filename>packagegroup-core-basic</filename> has been renamed to
+            <filename>packagegroup-core-full-cmdline</filename> to match.
+        </para>
+    </section>
+
+    <section id='migration-1.6-licensing'>
+        <title>Licensing</title>
+
+        <para>
+            The top-level <filename>LICENSE</filename> file has been changed
+            to better describe the license of the various components of
+            <link linkend='oe-core'>OE-Core</link>.
+            However, the licensing itself remains unchanged.
+        </para>
+
+        <para>
+            Normally, this change would not cause any side-effects.
+            However, some recipes point to this file within
+            <link linkend='var-LIC_FILES_CHKSUM'><filename>LIC_FILES_CHKSUM</filename></link>
+            (as <filename>${COREBASE}/LICENSE</filename>) and thus the
+            accompanying checksum must be changed from
+            3f40d7994397109285ec7b81fdeb3b58 to
+            4d92cd373abda3937c2bc47fbc49d690.
+            A better alternative is to have
+            <filename>LIC_FILES_CHKSUM</filename> point to a file
+            describing the license that is distributed with the source
+            that the recipe is building, if possible, rather than pointing
+            to <filename>${COREBASE}/LICENSE</filename>.
+        </para>
+    </section>
+
+    <section id='migration-1.6-cflags-options'>
+        <title><filename>CFLAGS</filename> Options</title>
+
+        <para>
+            The "-fpermissive" option has been removed from the default
+            <link linkend='var-CFLAGS'><filename>CFLAGS</filename></link>
+            value.
+            You need to take action on individual recipes that fail when
+            building with this option.
+            You need to either patch the recipes to fix the issues reported by
+            the compiler, or you need to add "-fpermissive" to
+            <filename>CFLAGS</filename> in the recipes.
+        </para>
+    </section>
+
+    <section id='migration-1.6-custom-images'>
+        <title>Custom Image Output Types</title>
+
+        <para>
+            Custom image output types, as selected using
+            <link linkend='var-IMAGE_FSTYPES'><filename>IMAGE_FSTYPES</filename></link>,
+            must declare their dependencies on other image types (if any) using
+            a new
+            <link linkend='var-IMAGE_TYPEDEP'><filename>IMAGE_TYPEDEP</filename></link>
+            variable.
+        </para>
+    </section>
+
+    <section id='migration-1.6-do-package-write-task'>
+        <title>Tasks</title>
+
+        <para>
+            The <filename>do_package_write</filename> task has been removed.
+            The task is no longer needed.
+        </para>
+    </section>
+
+    <section id='migration-1.6-update-alternatives-provider'>
+        <title><filename>update-alternative</filename> Provider</title>
+
+        <para>
+            The default <filename>update-alternatives</filename> provider has
+            been changed from <filename>opkg</filename> to
+            <filename>opkg-utils</filename>.
+            This change resolves some troublesome circular dependencies.
+            The runtime package has also been renamed from
+            <filename>update-alternatives-cworth</filename>
+            to <filename>update-alternatives-opkg</filename>.
+        </para>
+    </section>
+
+    <section id='migration-1.6-virtclass-overrides'>
+        <title><filename>virtclass</filename> Overrides</title>
+
+        <para>
+            The <filename>virtclass</filename> overrides are now deprecated.
+            Use the equivalent class overrides instead (e.g.
+            <filename>virtclass-native</filename> becomes
+            <filename>class-native</filename>.)
+        </para>
+    </section>
+
+    <section id='migration-1.6-removed-renamed-recipes'>
+        <title>Removed and Renamed Recipes</title>
+
+        <para>
+            The following recipes have been removed:
+            <itemizedlist>
+                <listitem><para><filename>packagegroup-toolset-native</filename> -
+                    This recipe is largely unused.
+                    </para></listitem>
+                <listitem><para><filename>linux-yocto-3.8</filename> -
+                    Support for the Linux yocto 3.8 kernel has been dropped.
+                    Support for the 3.10 and 3.14 kernels have been added
+                    with the <filename>linux-yocto-3.10</filename> and
+                    <filename>linux-yocto-3.14</filename> recipes.
+                    </para></listitem>
+                <listitem><para><filename>ocf-linux</filename> -
+                    This recipe has been functionally replaced using
+                    <filename>cryptodev-linux</filename>.
+                    </para></listitem>
+                <listitem><para><filename>genext2fs</filename> -
+                    <filename>genext2fs</filename> is no longer used by the
+                    build system and is unmaintained upstream.
+                    </para></listitem>
+                <listitem><para><filename>js</filename> -
+                    This provided an ancient version of Mozilla's javascript
+                    engine that is no longer needed.
+                    </para></listitem>
+                <listitem><para><filename>zaurusd</filename> -
+                    The recipe has been moved to the
+                    <filename>meta-handheld</filename> layer.
+                    </para></listitem>
+                <listitem><para><filename>eglibc 2.17</filename> -
+                    Replaced by the <filename>eglibc 2.19</filename>
+                    recipe.
+                    </para></listitem>
+                <listitem><para><filename>gcc 4.7.2</filename> -
+                    Replaced by the now stable
+                    <filename>gcc 4.8.2</filename>.
+                    </para></listitem>
+                <listitem><para><filename>external-sourcery-toolchain</filename> -
+                    this recipe is now maintained in the
+                    <filename>meta-sourcery</filename> layer.
+                    </para></listitem>
+                <listitem><para><filename>linux-libc-headers-yocto 3.4+git</filename> -
+                    Now using version 3.10 of the
+                    <filename>linux-libc-headers</filename> by default.
+                    </para></listitem>
+                <listitem><para><filename>meta-toolchain-gmae</filename> -
+                    This recipe is obsolete.
+                    </para></listitem>
+                <listitem><para><filename>packagegroup-core-sdk-gmae</filename> -
+                    This recipe is obsolete.
+                    </para></listitem>
+                <listitem><para><filename>packagegroup-core-standalone-gmae-sdk-target</filename> -
+                    This recipe is obsolete.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-1.6-removed-classes'>
+        <title>Removed Classes</title>
+
+        <para>
+            The following classes have become obsolete and have been removed:
+            <itemizedlist>
+                <listitem><para><filename>module_strip</filename>
+                    </para></listitem>
+                <listitem><para><filename>pkg_metainfo</filename>
+                    </para></listitem>
+                <listitem><para><filename>pkg_distribute</filename>
+                    </para></listitem>
+                <listitem><para><filename>image-empty</filename>
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-1.6-reference-bsps'>
+        <title>Reference Board Support Packages (BSPs)</title>
+
+        <para>
+            The following reference BSPs changes occurred:
+            <itemizedlist>
+                <listitem><para>The BeagleBoard
+                    (<filename>beagleboard</filename>) ARM reference hardware
+                    has been replaced by the BeagleBone
+                    (<filename>beaglebone</filename>) hardware.
+                    </para></listitem>
+                <listitem><para>The RouterStation Pro
+                    (<filename>routerstationpro</filename>) MIPS reference
+                    hardware has been replaced by the EdgeRouter Lite
+                    (<filename>edgerouter</filename>) hardware.
+                    </para></listitem>
+            </itemizedlist>
+            The previous reference BSPs for the
+            <filename>beagleboard</filename> and
+            <filename>routerstationpro</filename> machines are still available
+            in a new <filename>meta-yocto-bsp-old</filename> layer in the
+            <ulink url='&YOCTO_GIT_URL;'>Source Repositories</ulink>
+            at
+            <ulink url='http://git.yoctoproject.org/cgit/cgit.cgi/meta-yocto-bsp-old/'>http://git.yoctoproject.org/cgit/cgit.cgi/meta-yocto-bsp-old/</ulink>.
+        </para>
+    </section>
+</section>
+
+<section id='moving-to-the-yocto-project-1.7-release'>
+    <title>Moving to the Yocto Project 1.7 Release</title>
+
+    <para>
+        This section provides migration information for moving to the
+        Yocto Project 1.7 Release from the prior release.
+    </para>
+
+    <section id='migration-1.7-changes-to-setting-qemu-packageconfig-options'>
+        <title>Changes to Setting QEMU <filename>PACKAGECONFIG</filename> Options in <filename>local.conf</filename></title>
+
+        <para>
+            The QEMU recipe now uses a number of
+            <link linkend='var-PACKAGECONFIG'><filename>PACKAGECONFIG</filename></link>
+            options to enable various optional features.
+            The method used to set defaults for these options means that
+            existing
+            <filename>local.conf</filename> files will need to be be
+            modified to append to <filename>PACKAGECONFIG</filename> for
+            <filename>qemu-native</filename> and
+            <filename>nativesdk-qemu</filename> instead of setting it.
+            In other words, to enable graphical output for QEMU, you should
+            now have these lines in <filename>local.conf</filename>:
+            <literallayout class='monospaced'>
+     PACKAGECONFIG_append_pn-qemu-native = " sdl"
+     PACKAGECONFIG_append_pn-nativesdk-qemu = " sdl"
+            </literallayout>
+        </para>
+    </section>
+
+    <section id='migration-1.7-minimum-git-version'>
+        <title>Minimum Git version</title>
+
+        <para>
+            The minimum
+            <ulink url='&YOCTO_DOCS_OM_URL;#git'>Git</ulink> version
+            required on the build host is now 1.7.8 because the
+            <filename>--list</filename> option is now required by
+            BitBake's Git fetcher.
+            As always, if your host distribution does not provide a version of
+            Git that meets this requirement, you can use the
+            <filename>buildtools-tarball</filename> that does.
+            See the
+            "<link linkend='required-git-tar-python-and-gcc-versions'>Required Git, tar, Python and gcc Versions</link>"
+            section for more information.
+        </para>
+    </section>
+
+    <section id='migration-1.7-autotools-class-changes'>
+        <title>Autotools Class Changes</title>
+
+        <para>
+            The following
+            <link linkend='ref-classes-autotools'><filename>autotools</filename></link>
+            class changes occurred:
+            <itemizedlist>
+                <listitem><para><emphasis>
+                    A separate build directory is now used by default:</emphasis>
+                    The <filename>autotools</filename> class has been changed
+                    to use a directory for building
+                    (<link linkend='var-B'><filename>B</filename></link>),
+                    which is separate from the source directory
+                    (<link linkend='var-S'><filename>S</filename></link>).
+                    This is commonly referred to as
+                    <filename>B != S</filename>, or an out-of-tree build.</para>
+                    <para>If the software being built is already capable of
+                    building in a directory separate from the source, you
+                    do not need to do anything.
+                    However, if the software is not capable of being built
+                    in this manner, you will
+                    need to either patch the software so that it can build
+                    separately, or you will need to change the recipe to
+                    inherit the
+                    <link linkend='ref-classes-autotools'><filename>autotools-brokensep</filename></link>
+                    class instead of the <filename>autotools</filename> or
+                    <filename>autotools_stage</filename> classes.
+                    </para></listitem>
+                <listitem><para><emphasis>
+                    The <filename>--foreign</filename> option is
+                    no longer passed to <filename>automake</filename> when
+                    running <filename>autoconf</filename>:</emphasis>
+                    This option tells <filename>automake</filename> that a
+                    particular software package does not follow the GNU
+                    standards and therefore should not be expected
+                    to distribute certain files such as
+                    <filename>ChangeLog</filename>,
+                    <filename>AUTHORS</filename>, and so forth.
+                    Because the majority of upstream software packages already
+                    tell <filename>automake</filename> to enable foreign mode
+                    themselves, the option is mostly superfluous.
+                    However, some recipes will need patches for this change.
+                    You can easily make the change by patching
+                    <filename>configure.ac</filename> so that it passes
+                    "foreign" to <filename>AM_INIT_AUTOMAKE()</filename>.
+                    See
+                    <ulink url='http://cgit.openembedded.org/openembedded-core/commit/?id=01943188f85ce6411717fb5bf702d609f55813f2'>this commit</ulink>
+                    for an example showing how to make the patch.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-1.7-binary-configuration-scripts-disabled'>
+        <title>Binary Configuration Scripts Disabled</title>
+
+        <para>
+            Some of the core recipes that package binary configuration scripts
+            now disable the scripts due to the
+            scripts previously requiring error-prone path substitution.
+            Software that links against these libraries using these scripts
+            should use the much more robust <filename>pkg-config</filename>
+            instead.
+            The list of recipes changed in this version (and their
+            configuration scripts) is as follows:
+            <literallayout class='monospaced'>
+     directfb (directfb-config)
+     freetype (freetype-config)
+     gpgme (gpgme-config)
+     libassuan (libassuan-config)
+     libcroco (croco-6.0-config)
+     libgcrypt (libgcrypt-config)
+     libgpg-error (gpg-error-config)
+     libksba (ksba-config)
+     libpcap (pcap-config)
+     libpcre (pcre-config)
+     libpng (libpng-config, libpng16-config)
+     libsdl (sdl-config)
+     libusb-compat (libusb-config)
+     libxml2 (xml2-config)
+     libxslt (xslt-config)
+     ncurses (ncurses-config)
+     neon (neon-config)
+     npth (npth-config)
+     pth (pth-config)
+     taglib (taglib-config)
+            </literallayout>
+            Additionally, support for <filename>pkg-config</filename> has been
+            added to some recipes in the previous list in the rare cases
+            where the upstream software package does not already provide
+            it.
+        </para>
+    </section>
+
+    <section id='migration-1.7-glibc-replaces-eglibc'>
+        <title><filename>eglibc 2.19</filename> Replaced with <filename>glibc 2.20</filename></title>
+
+        <para>
+            Because <filename>eglibc</filename> and
+            <filename>glibc</filename> were already fairly close, this
+            replacement should not require any significant changes to other
+            software that links to <filename>eglibc</filename>.
+            However, there were a number of minor changes in
+            <filename>glibc 2.20</filename> upstream that could require
+            patching some software (e.g. the removal of the
+            <filename>_BSD_SOURCE</filename> feature test macro).
+        </para>
+
+        <para>
+            <filename>glibc 2.20</filename> requires version 2.6.32 or greater
+            of the Linux kernel.
+            Thus, older kernels will no longer be usable in conjunction with it.
+        </para>
+
+        <para>
+            For full details on the changes in <filename>glibc 2.20</filename>,
+            see the upstream release notes
+            <ulink url='https://sourceware.org/ml/libc-alpha/2014-09/msg00088.html'>here</ulink>.
+        </para>
+    </section>
+
+    <section id='migration-1.7-kernel-module-autoloading'>
+        <title>Kernel Module Autoloading</title>
+
+        <para>
+            The
+            <link linkend='var-module_autoload'><filename>module_autoload_*</filename></link>
+            variable is now deprecated and a new
+            <link linkend='var-KERNEL_MODULE_AUTOLOAD'><filename>KERNEL_MODULE_AUTOLOAD</filename></link>
+            variable should be used instead.
+            Also,
+            <link linkend='var-module_conf'><filename>module_conf_*</filename></link>
+            must now be used in conjunction with a new
+            <link linkend='var-KERNEL_MODULE_PROBECONF'><filename>KERNEL_MODULE_PROBECONF</filename></link>
+            variable.
+            The new variables no longer require you to specify the module name
+            as part of the variable name.
+            This change not only simplifies usage but also allows the values
+            of these variables to be appropriately incorporated into task
+            signatures and thus trigger the appropriate tasks to re-execute
+            when changed.
+            You should replace any references to
+            <filename>module_autoload_*</filename> with
+            <filename>KERNEL_MODULE_AUTOLOAD</filename>, and add any modules
+            for which <filename>module_conf_*</filename> is specified to
+            <filename>KERNEL_MODULE_PROBECONF</filename>.
+        </para>
+    </section>
+
+    <section id='migration-1.7-qa-check-changes'>
+        <title>QA Check Changes</title>
+
+        <para>
+            The following changes have occurred to the QA check process:
+            <itemizedlist>
+                <listitem><para>
+                    Additional QA checks <filename>file-rdeps</filename>
+                    and <filename>build-deps</filename> have been added in
+                    order to verify that file dependencies are satisfied
+                    (e.g. package contains a script requiring
+                    <filename>/bin/bash</filename>) and build-time dependencies
+                    are declared, respectively.
+                    For more information, please see the
+                    "<link linkend='ref-qa-checks'>QA Error and Warning Messages</link>"
+                    chapter.
+                    </para></listitem>
+                <listitem><para>
+                    Package QA checks are now performed during a new
+                    <link linkend='ref-tasks-package_qa'><filename>do_package_qa</filename></link>
+                    task rather than being part of the
+                    <link linkend='ref-tasks-package'><filename>do_package</filename></link>
+                    task.
+                    This allows more parallel execution.
+                    This change is unlikely to be an issue except for highly
+                    customized recipes that disable packaging tasks themselves
+                    by marking them as <filename>noexec</filename>.
+                    For those packages, you will need to disable the
+                    <filename>do_package_qa</filename> task as well.
+                    </para></listitem>
+                <listitem><para>
+                    Files being overwritten during the
+                    <link linkend='ref-tasks-populate_sysroot'><filename>do_populate_sysroot</filename></link>
+                    task now trigger an error instead of a warning.
+                    Recipes should not be overwriting files written to the
+                    sysroot by other recipes.
+                    If you have these types of recipes, you need to alter them
+                    so that they do not overwrite these files.</para>
+                    <para>You might now receive this error after changes in
+                    configuration or metadata resulting in orphaned files
+                    being left in the sysroot.
+                    If you do receive this error, the way to resolve the issue
+                    is to delete your
+                    <link linkend='var-TMPDIR'><filename>TMPDIR</filename></link>
+                    or to move it out of the way and then re-start the build.
+                    Anything that has been fully built up to that point and
+                    does not need rebuilding will be restored from the shared
+                    state cache and the rest of the build will be able to
+                    proceed as normal.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-1.7-removed-recipes'>
+        <title>Removed Recipes</title>
+
+        <para>
+            The following recipes have been removed:
+            <itemizedlist>
+                <listitem><para>
+                    <filename>x-load</filename>:
+                    This recipe has been superseded by
+                    U-boot SPL for all Cortex-based TI SoCs.
+                    For legacy boards, the <filename>meta-ti</filename>
+                    layer, which contains a maintained recipe, should be used
+                    instead.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>ubootchart</filename>:
+                    This recipe is obsolete.
+                    A <filename>bootchart2</filename> recipe has been added
+                    to functionally replace it.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>linux-yocto 3.4</filename>:
+                    Support for the linux-yocto 3.4 kernel has been dropped.
+                    Support for the 3.10 and 3.14 kernels remains, while
+                    support for version 3.17 has been added.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>eglibc</filename> has been removed in favor of
+                    <filename>glibc</filename>.
+                    See the
+                    "<link linkend='migration-1.7-glibc-replaces-eglibc'><filename>eglibc 2.19</filename> Replaced with <filename>glibc 2.20</filename></link>"
+                    section for more information.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-1.7-miscellaneous-changes'>
+        <title>Miscellaneous Changes</title>
+
+        <para>
+            The following miscellaneous change occurred:
+            <itemizedlist>
+                <listitem><para>
+                    The build history feature now writes
+                    <filename>build-id.txt</filename> instead of
+                    <filename>build-id</filename>.
+                    Additionally, <filename>build-id.txt</filename>
+                    now contains the full build header as printed by
+                    BitBake upon starting the build.
+                    You should manually remove old "build-id" files from your
+                    existing build history repositories to avoid confusion.
+                    For information on the build history feature, see the
+                    "<ulink url='&YOCTO_DOCS_DEV_URL;#maintaining-build-output-quality'>Maintaining Build Output Quality</ulink>"
+                    section in the Yocto Project Development Tasks Manual.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+</section>
+
+<section id='moving-to-the-yocto-project-1.8-release'>
+    <title>Moving to the Yocto Project 1.8 Release</title>
+
+    <para>
+        This section provides migration information for moving to the
+        Yocto Project 1.8 Release from the prior release.
+    </para>
+
+    <section id='migration-1.8-removed-recipes'>
+        <title>Removed Recipes</title>
+
+        <para>
+            The following recipes have been removed:
+            <itemizedlist>
+                <listitem><para><filename>owl-video</filename>:
+                    Functionality replaced by <filename>gst-player</filename>.
+                    </para></listitem>
+                <listitem><para><filename>gaku</filename>:
+                    Functionality replaced by <filename>gst-player</filename>.
+                    </para></listitem>
+                <listitem><para><filename>gnome-desktop</filename>:
+                    This recipe is now available in
+                    <filename>meta-gnome</filename> and is no longer needed.
+                    </para></listitem>
+                <listitem><para><filename>gsettings-desktop-schemas</filename>:
+                    This recipe is now available in
+                    <filename>meta-gnome</filename> and is no longer needed.
+                    </para></listitem>
+                <listitem><para><filename>python-argparse</filename>:
+                    The <filename>argparse</filename> module is already
+                    provided in the default Python distribution in a
+                    package named <filename>python-argparse</filename>.
+                    Consequently, the separate
+                    <filename>python-argparse</filename> recipe is no
+                    longer needed.
+                    </para></listitem>
+                <listitem><para><filename>telepathy-python, libtelepathy, telepathy-glib, telepathy-idle, telepathy-mission-control</filename>:
+                    All these recipes have moved to
+                    <filename>meta-oe</filename> and are consequently no
+                    longer needed by any recipes in OpenEmbedded-Core.
+                    </para></listitem>
+                <listitem><para><filename>linux-yocto_3.10</filename> and <filename>linux-yocto_3.17</filename>:
+                    Support for the linux-yocto 3.10 and 3.17 kernels has been
+                    dropped.
+                    Support for the 3.14 kernel remains, while support for
+                    3.19 kernel has been added.
+                    </para></listitem>
+                <listitem><para><filename>poky-feed-config-opkg</filename>:
+                    This recipe has become obsolete and is no longer needed.
+                    Use <filename>distro-feed-config</filename> from
+                    <filename>meta-oe</filename> instead.
+                    </para></listitem>
+                <listitem><para><filename>libav 0.8.x</filename>:
+                    <filename>libav 9.x</filename> is now used.
+                    </para></listitem>
+                <listitem><para><filename>sed-native</filename>:
+                    No longer needed.
+                    A working version of <filename>sed</filename> is expected
+                    to be provided by the host distribution.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-1.8-bluez'>
+        <title>BlueZ 4.x / 5.x Selection</title>
+
+        <para>
+            Proper built-in support for selecting BlueZ 5.x in preference
+            to the default of 4.x now exists.
+            To use BlueZ 5.x, simply add "bluez5" to your
+            <link linkend='var-DISTRO_FEATURES'><filename>DISTRO_FEATURES</filename></link>
+            value.
+            If you had previously added append files
+            (<filename>*.bbappend</filename>) to make this selection, you can
+            now remove them.
+        </para>
+
+        <para>
+            Additionally, a <filename>bluetooth</filename> class has been added
+            to make selection of the appropriate bluetooth support within a
+            recipe a little easier.
+            If you wish to make use of this class in a recipe, add something
+            such as the following:
+            <literallayout class='monospaced'>
+     inherit bluetooth
+     PACKAGECONFIG ??= "${@bb.utils.contains('DISTRO_FEATURES', 'bluetooth', '${BLUEZ}', '', d)}"
+     PACKAGECONFIG[bluez4] = "--enable-bluetooth,--disable-bluetooth,bluez4"
+     PACKAGECONFIG[bluez5] = "--enable-bluez5,--disable-bluez5,bluez5"
+            </literallayout>
+        </para>
+    </section>
+
+    <section id='migration-1.8-kernel-build-changes'>
+        <title>Kernel Build Changes</title>
+
+        <para>
+            The kernel build process was changed to place the source
+            in a common shared work area and to place build artifacts
+            separately in the source code tree.
+            In theory, migration paths have been provided for most common
+            usages in kernel recipes but this might not work in all cases.
+            In particular, users need to ensure that
+            <filename>${S}</filename> (source files) and
+            <filename>${B}</filename> (build artifacts) are used
+            correctly in functions such as
+            <link linkend='ref-tasks-configure'><filename>do_configure</filename></link>
+            and
+            <link linkend='ref-tasks-install'><filename>do_install</filename></link>.
+            For kernel recipes that do not inherit from
+            <filename>kernel-yocto</filename> or include
+            <filename>linux-yocto.inc</filename>, you might wish to
+            refer to the <filename>linux.inc</filename> file in the
+            <filename>meta-oe</filename> layer for the kinds of changes you
+            need to make.
+            For reference, here is the
+            <ulink url='http://cgit.openembedded.org/meta-openembedded/commit/meta-oe/recipes-kernel/linux/linux.inc?id=fc7132ede27ac67669448d3d2845ce7d46c6a1ee'>commit</ulink>
+            where the <filename>linux.inc</filename> file in
+            <filename>meta-oe</filename> was updated.
+        </para>
+
+        <para>
+            Recipes that rely on the kernel source code and do not inherit
+            the module classes might need to add explicit dependencies on
+            the <filename>do_shared_workdir</filename> kernel task, for example:
+            <literallayout class='monospaced'>
+     do_configure[depends] += "virtual/kernel:do_shared_workdir"
+            </literallayout>
+        </para>
+    </section>
+
+    <section id='migration-1.8-ssl'>
+        <title>SSL 3.0 is Now Disabled in OpenSSL</title>
+
+        <para>
+            SSL 3.0 is now disabled when building OpenSSL.
+            Disabling SSL 3.0 avoids any lingering instances of the POODLE
+            vulnerability.
+            If you feel you must re-enable SSL 3.0, then you can add an
+            append file (<filename>*.bbappend</filename>) for the
+            <filename>openssl</filename> recipe to remove "-no-ssl3"
+            from
+            <link linkend='var-EXTRA_OECONF'><filename>EXTRA_OECONF</filename></link>.
+        </para>
+    </section>
+
+    <section id='migration-1.8-default-sysroot-poisoning'>
+        <title>Default Sysroot Poisoning</title>
+
+        <para>
+            <filename>gcc's</filename> default sysroot and include directories
+            are now "poisoned".
+            In other words, the sysroot and include directories are being
+            redirected to a non-existent location in order to catch when
+            host directories are being used due to the correct options not
+            being passed.
+            This poisoning applies both to the cross-compiler used within the
+            build and to the cross-compiler produced in the SDK.
+        </para>
+
+        <para>
+            If this change causes something in the build to fail, it almost
+            certainly means the various compiler flags and commands are not
+            being passed correctly to the underlying piece of software.
+            In such cases, you need to take corrective steps.
+        </para>
+    </section>
+
+    <section id='migration-1.8-rebuild-improvements'>
+        <title>Rebuild Improvements</title>
+
+        <para>
+            Changes have been made to the
+            <link linkend='ref-classes-base'><filename>base</filename></link>,
+            <link linkend='ref-classes-autotools'><filename>autotools</filename></link>,
+            and
+            <link linkend='ref-classes-cmake'><filename>cmake</filename></link>
+            classes to clean out generated files when the
+            <link linkend='ref-tasks-configure'><filename>do_configure</filename></link>
+            task needs to be re-executed.
+        </para>
+
+        <para>
+            One of the improvements is to attempt to run "make clean" during
+            the <filename>do_configure</filename> task if a
+            <filename>Makefile</filename> exists.
+            Some software packages do not provide a working clean target
+            within their make files.
+            If you have such recipes, you need to set
+            <link linkend='var-CLEANBROKEN'><filename>CLEANBROKEN</filename></link>
+            to "1" within the recipe, for example:
+            <literallayout class='monospaced'>
+     CLEANBROKEN = "1"
+            </literallayout>
+        </para>
+    </section>
+
+    <section id='migration-1.8-qa-check-and-validation-changes'>
+        <title>QA Check and Validation Changes</title>
+
+        <para>
+            The following QA Check and Validation Changes have occurred:
+            <itemizedlist>
+                <listitem><para>
+                    Usage of <filename>PRINC</filename>
+                    previously triggered a warning.
+                    It now triggers an error.
+                    You should remove any remaining usage of
+                    <filename>PRINC</filename> in any recipe or append file.
+                    </para></listitem>
+                <listitem><para>
+                    An additional QA check has been added to detect usage of
+                    <filename>${D}</filename> in
+                    <link linkend='var-FILES'><filename>FILES</filename></link>
+                    values where
+                    <link linkend='var-D'><filename>D</filename></link> values
+                    should not be used at all.
+                    The same check ensures that <filename>$D</filename> is used
+                    in
+                    <filename>pkg_preinst/pkg_postinst/pkg_prerm/pkg_postrm</filename>
+                    functions instead of <filename>${D}</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    <link linkend='var-S'><filename>S</filename></link> now
+                    needs to be set to a valid value within a recipe.
+                    If <filename>S</filename> is not set in the recipe, the
+                    directory is not automatically created.
+                    If <filename>S</filename> does not point to a directory
+                    that exists at the time the
+                    <link linkend='ref-tasks-unpack'><filename>do_unpack</filename></link>
+                    task finishes, a warning will be shown.
+                    </para></listitem>
+                <listitem><para>
+                    <link linkend='var-LICENSE'><filename>LICENSE</filename></link>
+                    is now validated for correct formatting of multiple
+                    licenses.
+                    If the format is invalid (e.g. multiple licenses are
+                    specified with no operators to specify how the multiple
+                    licenses interact), then a warning will be shown.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-1.8-miscellaneous-changes'>
+        <title>Miscellaneous Changes</title>
+
+        <para>
+            The following miscellaneous changes have occurred:
+            <itemizedlist>
+                <listitem><para>
+                    The <filename>send-error-report</filename> script now
+                    expects a "-s" option to be specified before the server
+                    address.
+                    This assumes a server address is being specified.
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>oe-pkgdata-util</filename> script now
+                    expects a "-p" option to be specified before the
+                    <filename>pkgdata</filename> directory, which is now
+                    optional.
+                    If the <filename>pkgdata</filename> directory is not
+                    specified, the script will run BitBake to query
+                    <link linkend='var-PKGDATA_DIR'><filename>PKGDATA_DIR</filename></link>
+                    from the build environment.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+</section>
+
+<section id='moving-to-the-yocto-project-2.0-release'>
+    <title>Moving to the Yocto Project 2.0 Release</title>
+
+    <para>
+        This section provides migration information for moving to the
+        Yocto Project 2.0 Release from the prior release.
+    </para>
+
+    <section id='migration-2.0-gcc-5'>
+        <title>GCC 5</title>
+
+        <para>
+            The default compiler is now GCC 5.2.
+            This change has required fixes for compilation errors in a number
+            of other recipes.
+        </para>
+
+        <para>
+            One important example is a fix for when the Linux kernel freezes at
+            boot time on ARM when built with GCC 5.
+            If you are using your own kernel recipe or source tree and
+            building for ARM, you will likely need to apply this
+            <ulink url='https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit?id=a077224fd35b2f7fbc93f14cf67074fc792fbac2'>patch</ulink>.
+            The standard <filename>linux-yocto</filename> kernel source tree
+            already has a workaround for the same issue.
+        </para>
+
+        <para>
+            For further details, see
+            <ulink url='https://gcc.gnu.org/gcc-5/changes.html'></ulink> and
+            the porting guide at
+            <ulink url='https://gcc.gnu.org/gcc-5/porting_to.html'></ulink>.
+        </para>
+
+        <para>
+            Alternatively, you can switch back to GCC 4.9 or 4.8 by
+            setting <filename>GCCVERSION</filename> in your configuration,
+            as follows:
+            <literallayout class='monospaced'>
+     GCCVERSION = "4.9%"
+            </literallayout>
+        </para>
+    </section>
+
+    <section id='migration-2.0-Gstreamer-0.10-removed'>
+        <title>Gstreamer 0.10 Removed</title>
+
+        <para>
+            Gstreamer 0.10 has been removed in favor of Gstreamer 1.x.
+            As part of the change, recipes for Gstreamer 0.10 and related
+            software are now located
+            in <filename>meta-multimedia</filename>.
+            This change results in Qt4 having Phonon and Gstreamer
+            support in QtWebkit disabled by default.
+        </para>
+    </section>
+
+    <section id='migration-2.0-removed-recipes'>
+        <title>Removed Recipes</title>
+
+        <para>
+            The following recipes have been moved or removed:
+            <itemizedlist>
+                <listitem><para>
+                    <filename>bluez4</filename>: The recipe is obsolete and
+                    has been moved due to <filename>bluez5</filename>
+                    becoming fully integrated.
+                    The <filename>bluez4</filename> recipe now resides in
+                    <filename>meta-oe</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>gamin</filename>: The recipe is obsolete and
+                    has been removed.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>gnome-icon-theme</filename>: The recipe's
+                    functionally has been replaced by
+                    <filename>adwaita-icon-theme</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    Gstreamer 0.10 Recipes: Recipes for Gstreamer 0.10 have
+                    been removed in favor of the recipes for Gstreamer 1.x.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>insserv</filename>: The recipe is obsolete and
+                    has been removed.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>libunique</filename>: The recipe is no longer
+                    used and has been moved to <filename>meta-oe</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>midori</filename>: The recipe's functionally
+                    has been replaced by <filename>epiphany</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>python-gst</filename>: The recipe is obsolete
+                    and has been removed since it only contains bindings for
+                    Gstreamer 0.10.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>qt-mobility</filename>: The recipe is obsolete and
+                    has been removed since it requires
+                    <filename>Gstreamer 0.10</filename>, which has been
+                    replaced.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>subversion</filename>: All 1.6.x versions of this
+                    recipe have been removed.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>webkit-gtk</filename>: The older 1.8.3 version
+                    of this recipe has been removed in favor of
+                    <filename>webkitgtk</filename>.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.0-bitbake-datastore-improvements'>
+        <title>BitBake datastore improvements</title>
+
+        <para>
+            The method by which BitBake's datastore handles overrides has
+            changed.
+            Overrides are now applied dynamically and
+            <filename>bb.data.update_data()</filename> is now a no-op.
+            Thus, <filename>bb.data.update_data()</filename> is no longer
+            required in order to apply the correct overrides.
+            In practice, this change is unlikely to require any changes to
+            Metadata.
+            However, these minor changes in behavior exist:
+            <itemizedlist>
+                <listitem><para>
+                    All potential overrides are now visible in the variable
+                    history as seen when you run the following:
+                    <literallayout class='monospaced'>
+     $ bitbake -e
+                    </literallayout>
+                    </para></listitem>
+                <listitem><para>
+                    <filename>d.delVar('</filename><replaceable>VARNAME</replaceable><filename>')</filename> and
+                    <filename>d.setVar('</filename><replaceable>VARNAME</replaceable><filename>', None)</filename>
+                    result in the variable and all of its overrides being
+                    cleared out.
+                    Before the change, only the non-overridden values
+                    were cleared.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.0-shell-message-function-changes'>
+        <title>Shell Message Function Changes</title>
+
+        <para>
+            The shell versions of the BitBake message functions (i.e.
+            <filename>bbdebug</filename>, <filename>bbnote</filename>,
+            <filename>bbwarn</filename>, <filename>bbplain</filename>,
+            <filename>bberror</filename>, and <filename>bbfatal</filename>)
+            are now connected through to their BitBake equivalents
+            <filename>bb.debug()</filename>, <filename>bb.note()</filename>,
+            <filename>bb.warn()</filename>, <filename>bb.plain()</filename>,
+            <filename>bb.error()</filename>, and
+            <filename>bb.fatal()</filename>, respectively.
+            Thus, those message functions that you would expect to be printed
+            by the BitBake UI are now actually printed.
+            In practice, this change means two things:
+            <itemizedlist>
+                <listitem><para>
+                    If you now see messages on the console that you did not
+                    previously see as a result of this change, you might
+                    need to clean up the calls to
+                    <filename>bbwarn</filename>, <filename>bberror</filename>,
+                    and so forth.
+                    Or, you might want to simply remove the calls.
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>bbfatal</filename> message function now
+                    suppresses the full error log in the UI, which means any
+                    calls to <filename>bbfatal</filename> where you still
+                    wish to see the full error log should be replaced by
+                    <filename>die</filename> or
+                    <filename>bbfatal_log</filename>.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.0-extra-development-debug-package-cleanup'>
+        <title>Extra Development/Debug Package Cleanup</title>
+
+        <para>
+            The following recipes have had extra
+            <filename>dev/dbg</filename> packages removed:
+            <itemizedlist>
+                <listitem><para>
+                    <filename>acl</filename>
+                    </para></listitem>
+                <listitem><para>
+                    <filename>apmd</filename>
+                    </para></listitem>
+                <listitem><para>
+                    <filename>aspell</filename>
+                    </para></listitem>
+                <listitem><para>
+                    <filename>attr</filename>
+                    </para></listitem>
+                <listitem><para>
+                    <filename>augeas</filename>
+                    </para></listitem>
+                <listitem><para>
+                    <filename>bzip2</filename>
+                    </para></listitem>
+                <listitem><para>
+                    <filename>cogl</filename>
+                    </para></listitem>
+                <listitem><para>
+                    <filename>curl</filename>
+                    </para></listitem>
+                <listitem><para>
+                    <filename>elfutils</filename>
+                    </para></listitem>
+                <listitem><para>
+                    <filename>gcc-target</filename>
+                    </para></listitem>
+                <listitem><para>
+                    <filename>libgcc</filename>
+                    </para></listitem>
+                <listitem><para>
+                    <filename>libtool</filename>
+                    </para></listitem>
+                <listitem><para>
+                    <filename>libxmu</filename>
+                    </para></listitem>
+                <listitem><para>
+                    <filename>opkg</filename>
+                    </para></listitem>
+                <listitem><para>
+                    <filename>pciutils</filename>
+                    </para></listitem>
+                <listitem><para>
+                    <filename>rpm</filename>
+                    </para></listitem>
+                <listitem><para>
+                    <filename>sysfsutils</filename>
+                    </para></listitem>
+                <listitem><para>
+                    <filename>tiff</filename>
+                    </para></listitem>
+                <listitem><para>
+                    <filename>xz</filename>
+                    </para></listitem>
+            </itemizedlist>
+            All of the above recipes now conform to the standard packaging
+            scheme where a single <filename>-dev</filename>,
+            <filename>-dbg</filename>, and <filename>-staticdev</filename>
+            package exists per recipe.
+        </para>
+    </section>
+
+    <section id='migration-2.0-recipe-maintenance-tracking-data-moved-to-oe-core'>
+        <title>Recipe Maintenance Tracking Data Moved to OE-Core</title>
+
+        <para>
+            Maintenance tracking data for recipes that was previously part
+            of <filename>meta-yocto</filename> has been moved to
+            <link linkend='oe-core'>OE-Core</link>.
+            The change includes <filename>package_regex.inc</filename> and
+            <filename>distro_alias.inc</filename>, which are typically enabled
+            when using the <filename>distrodata</filename> class.
+            Additionally, the contents of
+            <filename>upstream_tracking.inc</filename> has now been split out
+            to the relevant recipes.
+        </para>
+    </section>
+
+    <section id='migration-2.0-automatic-stale-sysroot-file-cleanup'>
+        <title>Automatic Stale Sysroot File Cleanup</title>
+
+        <para>
+            Stale files from recipes that no longer exist in the current
+            configuration are now automatically removed from
+            sysroot as well as removed from
+            any other place managed by shared state.
+            This automatic cleanup means that the build system now properly
+            handles situations such as renaming the build system side of
+            recipes, removal of layers from
+            <filename>bblayers.conf</filename>, and
+            <link linkend='var-DISTRO_FEATURES'><filename>DISTRO_FEATURES</filename></link>
+            changes.
+        </para>
+
+        <para>
+            Additionally, work directories for old versions of recipes are
+            now pruned.
+            If you wish to disable pruning old work directories, you can set
+            the following variable in your configuration:
+            <literallayout class='monospaced'>
+     SSTATE_PRUNE_OBSOLETEWORKDIR = "0"
+            </literallayout>
+        </para>
+    </section>
+
+    <section id='migration-2.0-linux-yocto-kernel-metadata-repository-now-split-from-source'>
+        <title><filename>linux-yocto</filename> Kernel Metadata Repository Now Split from Source</title>
+
+        <para>
+            The <filename>linux-yocto</filename> tree has up to now been a
+            combined set of kernel changes and configuration (meta) data
+            carried in a single tree.
+            While this format is effective at keeping kernel configuration and
+            source modifications synchronized, it is not always obvious to
+            developers how to manipulate the Metadata as compared to the
+            source.
+        </para>
+
+        <para>
+            Metadata processing has now been removed from the
+            <link linkend='ref-classes-kernel-yocto'><filename>kernel-yocto</filename></link>
+            class and the external Metadata repository
+            <filename>yocto-kernel-cache</filename>, which has always been used
+            to seed the <filename>linux-yocto</filename> "meta" branch.
+            This separate <filename>linux-yocto</filename> cache repository
+            is now the primary location for this data.
+            Due to this change, <filename>linux-yocto</filename> is no longer
+            able to process combined trees.
+            Thus, if you need to have your own combined kernel repository,
+            you must do the split there as well and update your recipes
+            accordingly.
+            See the <filename>meta/recipes-kernel/linux/linux-yocto_4.1.bb</filename>
+            recipe for an example.
+        </para>
+    </section>
+
+    <section id='migration-2.0-additional-qa-checks'>
+        <title>Additional QA checks</title>
+
+        <para>
+            The following QA checks have been added:
+            <itemizedlist>
+                <listitem><para>
+                    Added a "host-user-contaminated" check for ownership
+                    issues for packaged files outside of
+                    <filename>/home</filename>.
+                    The check looks for files that are incorrectly owned by the
+                    user that ran BitBake instead of owned by a valid user in
+                    the target system.
+                    </para></listitem>
+                <listitem><para>
+                    Added an "invalid-chars" check for invalid (non-UTF8)
+                    characters in recipe metadata variable values
+                    (i.e.
+                    <link linkend='var-DESCRIPTION'><filename>DESCRIPTION</filename></link>,
+                    <link linkend='var-SUMMARY'><filename>SUMMARY</filename></link>,
+                    <link linkend='var-LICENSE'><filename>LICENSE</filename></link>,
+                    and
+                    <link linkend='var-SECTION'><filename>SECTION</filename></link>).
+                    Some package managers do not support these characters.
+                    </para></listitem>
+                <listitem><para>
+                    Added an "invalid-packageconfig" check for any options
+                    specified in
+                    <link linkend='var-PACKAGECONFIG'><filename>PACKAGECONFIG</filename></link>
+                    that do not match any <filename>PACKAGECONFIG</filename>
+                    option defined for the recipe.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.0-miscellaneous'>
+        <title>Miscellaneous Changes</title>
+
+        <para>
+            These additional changes exist:
+            <itemizedlist>
+                <listitem><para>
+                    <filename>gtk-update-icon-cache</filename> has been
+                    renamed to <filename>gtk-icon-utils</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>tools-profile</filename>
+                    <link linkend='var-IMAGE_FEATURES'><filename>IMAGE_FEATURES</filename></link>
+                    item as well as its corresponding packagegroup and
+                    <filename>packagegroup-core-tools-profile</filename> no
+                    longer bring in <filename>oprofile</filename>.
+                    Bringing in <filename>oprofile</filename> was originally
+                    added to aid compilation on resource-constrained
+                    targets.
+                    However, this aid has not been widely used and is not
+                    likely to be used going forward due to the more powerful
+                    target platforms and the existence of better
+                    cross-compilation tools.
+                    </para></listitem>
+                <listitem><para>
+                    The
+                    <link linkend='var-IMAGE_FSTYPES'><filename>IMAGE_FSTYPES</filename></link>
+                    variable's default value now specifies
+                    <filename>ext4</filename> instead of
+                    <filename>ext3</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    All support for the <filename>PRINC</filename>
+                    variable has been removed.
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>packagegroup-core-full-cmdline</filename>
+                    packagegroup no longer brings in
+                    <filename>lighttpd</filename> due to the fact that
+                    bringing in <filename>lighttpd</filename> is not really in
+                    line with the packagegroup's purpose, which is to add full
+                    versions of command-line tools that by default are
+                    provided by <filename>busybox</filename>.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+</section>
+
+<section id='moving-to-the-yocto-project-2.1-release'>
+    <title>Moving to the Yocto Project 2.1 Release</title>
+
+    <para>
+        This section provides migration information for moving to the
+        Yocto Project 2.1 Release from the prior release.
+    </para>
+
+    <section id='migration-2.1-variable-expansion-in-python-functions'>
+        <title>Variable Expansion in Python Functions</title>
+
+        <para>
+            Variable expressions, such as
+            <filename>${</filename><replaceable>VARNAME</replaceable><filename>}</filename>
+            no longer expand automatically within Python functions.
+            Suppressing expansion was done to allow Python functions to
+            construct shell scripts or other code for situations in which you
+            do not want such expressions expanded.
+            For any existing code that relies on these expansions, you need to
+            change the expansions to expand the value of individual
+            variables through <filename>d.getVar()</filename>.
+            To alternatively expand more complex expressions,
+            use <filename>d.expand()</filename>.
+        </para>
+    </section>
+
+    <section id='migration-2.1-overrides-must-now-be-lower-case'>
+        <title>Overrides Must Now be Lower-Case</title>
+
+        <para>
+            The convention for overrides has always been for them to be
+            lower-case characters.
+            This practice is now a requirement as BitBake's datastore now
+            assumes lower-case characters in order to give a slight performance
+            boost during parsing.
+            In practical terms, this requirement means that anything that ends
+            up in
+            <link linkend='var-OVERRIDES'><filename>OVERRIDES</filename></link>
+            must now appear in lower-case characters (e.g. values for
+            <filename>MACHINE</filename>, <filename>TARGET_ARCH</filename>,
+            <filename>DISTRO</filename>, and also recipe names if
+            <filename>_pn-</filename><replaceable>recipename</replaceable>
+            overrides are to be effective).
+        </para>
+    </section>
+
+    <section id='migration-2.1-expand-parameter-to-getvar-and-getvarflag-now-mandatory'>
+        <title>Expand Parameter to <filename>getVar()</filename> and
+            <filename>getVarFlag()</filename> is Now Mandatory</title>
+
+        <para>
+            The expand parameter to <filename>getVar()</filename> and
+            <filename>getVarFlag()</filename> previously defaulted to
+            False if not specified.
+            Now, however, no default exists so one must be specified.
+            You must change any <filename>getVar()</filename> calls that
+            do not specify the final expand parameter to calls that do specify
+            the parameter.
+            You can run the following <filename>sed</filename> command at the
+            base of a layer to make this change:
+            <literallayout class='monospaced'>
+     sed -e 's:\(\.getVar([^,()]*\)):\1, False):g' -i `grep -ril getVar *`
+     sed -e 's:\(\.getVarFlag([^,()]*, [^,()]*\)):\1, False):g' -i `grep -ril getVarFlag *`
+            </literallayout>
+            <note>
+                The reason for this change is that it prepares the way for
+                changing the default to True in a future Yocto Project release.
+                This future change is a much more sensible default than False.
+                However, the change needs to be made gradually as a sudden
+                change of the default would potentially cause side-effects
+                that would be difficult to detect.
+            </note>
+        </para>
+    </section>
+
+    <section id='migration-2.1-makefile-environment-changes'>
+        <title>Makefile Environment Changes</title>
+
+        <para>
+            <link linkend='var-EXTRA_OEMAKE'><filename>EXTRA_OEMAKE</filename></link>
+            now defaults to "" instead of "-e MAKEFLAGS=".
+            Setting <filename>EXTRA_OEMAKE</filename> to "-e MAKEFLAGS=" by
+            default was a historical accident that has required many classes
+            (e.g. <filename>autotools</filename>, <filename>module</filename>)
+            and recipes to override this default in order to work with
+            sensible build systems.
+            When upgrading to the release, you must edit any recipe that
+            relies upon this old default by either setting
+            <filename>EXTRA_OEMAKE</filename> back to "-e MAKEFLAGS=" or by
+            explicitly setting any required variable value overrides using
+            <filename>EXTRA_OEMAKE</filename>, which is typically only needed
+            when a Makefile sets a default value for a variable that is
+            inappropriate for cross-compilation using the "=" operator rather
+            than the "?=" operator.
+        </para>
+    </section>
+
+    <section id='migration-2.1-libexecdir-reverted-to-prefix-libexec'>
+        <title><filename>libexecdir</filename> Reverted to <filename>${prefix}/libexec</filename></title>
+
+        <para>
+            The use of <filename>${libdir}/${BPN}</filename> as
+            <filename>libexecdir</filename> is different as compared to all
+            other mainstream distributions, which either uses
+            <filename>${prefix}/libexec</filename> or
+            <filename>${libdir}</filename>.
+            The use is also contrary to the GNU Coding Standards
+            (i.e. <ulink url='https://www.gnu.org/prep/standards/html_node/Directory-Variables.html'></ulink>)
+            that suggest <filename>${prefix}/libexec</filename> and also
+            notes that any package-specific nesting should be done by the
+            package itself.
+            Finally, having <filename>libexecdir</filename> change between
+            recipes makes it very difficult for different recipes to invoke
+            binaries that have been installed into
+            <filename>libexecdir</filename>.
+            The Filesystem Hierarchy Standard
+            (i.e. <ulink url='http://refspecs.linuxfoundation.org/FHS_3.0/fhs/ch04s07.html'></ulink>)
+            now recognizes the use of <filename>${prefix}/libexec/</filename>,
+            giving distributions the choice between
+            <filename>${prefix}/lib</filename> or
+            <filename>${prefix}/libexec</filename> without breaking FHS.
+        </para>
+    </section>
+
+    <section id='migration-2.1-ac-cv-sizeof-off-t-no-longer-cached-in-site-files'>
+        <title><filename>ac_cv_sizeof_off_t</filename> is No Longer Cached in Site Files</title>
+
+        <para>
+            For recipes inheriting the
+            <link linkend='ref-classes-autotools'><filename>autotools</filename></link>
+            class, <filename>ac_cv_sizeof_off_t</filename> is no longer cached
+            in the site files for <filename>autoconf</filename>.
+            The reason for this change is because the
+            <filename>ac_cv_sizeof_off_t</filename> value is not necessarily
+            static per architecture as was previously assumed.
+            Rather, the value changes based on whether large file support is
+            enabled.
+            For most software that uses <filename>autoconf</filename>, this
+            change should not be a problem.
+            However, if you have a recipe that bypasses the standard
+            <link linkend='ref-tasks-configure'><filename>do_configure</filename></link>
+            task from the <filename>autotools</filename> class and the software
+            the recipe is building uses a very old version of
+            <filename>autoconf</filename>, the recipe might be incapable of
+            determining the correct size of <filename>off_t</filename> during
+            <filename>do_configure</filename>.
+        </para>
+
+        <para>
+            The best course of action is to patch the software as necessary
+            to allow the default implementation from the
+            <filename>autotools</filename> class to work such that
+            <filename>autoreconf</filename> succeeds and produces a working
+            configure script, and to remove the
+            overridden <filename>do_configure</filename> task such that the
+            default implementation does get used.
+        </para>
+    </section>
+
+    <section id='migration-2.1-image-generation-split-out-from-filesystem-generation'>
+        <title>Image Generation is Now Split Out from Filesystem Generation</title>
+
+        <para>
+            Previously, for image recipes the
+            <link linkend='ref-tasks-rootfs'><filename>do_rootfs</filename></link>
+            task assembled the filesystem and then from that filesystem
+            generated images.
+            With this Yocto Project release, image generation is split into
+            separate
+            <link linkend='ref-tasks-image'><filename>do_image_*</filename></link>
+            tasks for clarity both in operation and in the code.
+        </para>
+
+        <para>
+            For most cases, this change does not present any problems.
+            However, if you have made customizations that directly modify the
+            <filename>do_rootfs</filename> task or that mention
+            <filename>do_rootfs</filename>, you might need to update those
+            changes.
+            In particular, if you had added any tasks after
+            <filename>do_rootfs</filename>, you should make edits so that
+            those tasks are after the
+            <link linkend='ref-tasks-image-complete'><filename>do_image_complete</filename></link>
+            task rather than after <filename>do_rootfs</filename>
+            so that the your added tasks
+            run at the correct time.
+        </para>
+
+        <para>
+            A minor part of this restructuring is that the post-processing
+            definitions and functions have been moved from the
+            <link linkend='ref-classes-image'><filename>image</filename></link>
+            class to the
+            <link linkend='ref-classes-rootfs*'><filename>rootfs-postcommands</filename></link>
+            class.
+            Functionally, however, they remain unchanged.
+        </para>
+    </section>
+
+    <section id='migration-2.1-removed-recipes'>
+        <title>Removed Recipes</title>
+
+        <para>
+            The following recipes have been removed in the 2.1 release:
+            <itemizedlist>
+                <listitem><para><filename>gcc</filename> version 4.8:
+                    Versions 4.9 and 5.3 remain.
+                    </para></listitem>
+                <listitem><para><filename>qt4</filename>:
+                    All support for Qt 4.x has been moved out to a separate
+                    <filename>meta-qt4</filename> layer because Qt 4 is no
+                    longer supported upstream.
+                    </para></listitem>
+                <listitem><para><filename>x11vnc</filename>:
+                    Moved to the <filename>meta-oe</filename> layer.
+                    </para></listitem>
+                <listitem><para><filename>linux-yocto-3.14</filename>:
+                    No longer supported.
+                    </para></listitem>
+                <listitem><para><filename>linux-yocto-3.19</filename>:
+                    No longer supported.
+                    </para></listitem>
+                <listitem><para><filename>libjpeg</filename>:
+                    Replaced by the <filename>libjpeg-turbo</filename> recipe.
+                    </para></listitem>
+                <listitem><para><filename>pth</filename>:
+                    Became obsolete.
+                    </para></listitem>
+                <listitem><para><filename>liboil</filename>:
+                    Recipe is no longer needed and has been moved to the
+                    <filename>meta-multimedia</filename> layer.
+                    </para></listitem>
+                <listitem><para><filename>gtk-theme-torturer</filename>:
+                    Recipe is no longer needed and has been moved to the
+                    <filename>meta-gnome</filename> layer.
+                    </para></listitem>
+                <listitem><para><filename>gnome-mime-data</filename>:
+                    Recipe is no longer needed and has been moved to the
+                    <filename>meta-gnome</filename> layer.
+                    </para></listitem>
+                <listitem><para><filename>udev</filename>:
+                    Replaced by the <filename>eudev</filename> recipe for
+                    compatibility when using <filename>sysvinit</filename>
+                    with newer kernels.
+                    </para></listitem>
+                <listitem><para><filename>python-pygtk</filename>:
+                    Recipe became obsolete.
+                    </para></listitem>
+                <listitem><para><filename>adt-installer</filename>:
+                    Recipe became obsolete.
+                    See the
+                    "<link linkend='migration-2.1-adt-removed'>ADT Removed</link>"
+                    section for more information.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.1-class-changes'>
+        <title>Class Changes</title>
+
+        <para>
+            The following classes have changed:
+            <itemizedlist>
+                <listitem><para><filename>autotools_stage</filename>:
+                    Removed because the
+                    <link linkend='ref-classes-autotools'><filename>autotools</filename></link>
+                    class now provides its functionality.
+                    Recipes that inherited from
+                    <filename>autotools_stage</filename> should now inherit
+                    from <filename>autotools</filename> instead.
+                    </para></listitem>
+                <listitem><para><filename>boot-directdisk</filename>:
+                    Merged into the <filename>image-vm</filename>
+                    class.
+                    The <filename>boot-directdisk</filename> class was rarely
+                    directly used.
+                    Consequently, this change should not cause any issues.
+                    </para></listitem>
+                <listitem><para><filename>bootimg</filename>:
+                    Merged into the
+                    <link linkend='ref-classes-image-live'><filename>image-live</filename></link>
+                    class.
+                    The <filename>bootimg</filename> class was rarely
+                    directly used.
+                    Consequently, this change should not cause any issues.
+                    </para></listitem>
+                <listitem><para><filename>packageinfo</filename>:
+                    Removed due to its limited use by the Hob UI, which has
+                    itself been removed.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.1-build-system-ui-changes'>
+        <title>Build System User Interface Changes</title>
+
+        <para>
+            The following changes have been made to the build system user
+            interface:
+            <itemizedlist>
+                <listitem><para><emphasis>Hob GTK+-based UI</emphasis>:
+                    Removed because it is unmaintained and based on the
+                    outdated GTK+ 2 library.
+                    The Toaster web-based UI is much more capable and is
+                    actively maintained.
+                    See the
+                    "<ulink url='&YOCTO_DOCS_TOAST_URL;#using-the-toaster-web-interface'>Using the Toaster Web Interface</ulink>"
+                    section in the Toaster User Manual for more
+                    information on this interface.
+                    </para></listitem>
+                <listitem><para><emphasis>"puccho" BitBake UI</emphasis>:
+                    Removed because is unmaintained and no longer useful.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.1-adt-removed'>
+        <title>ADT Removed</title>
+
+        <para>
+            The Application Development Toolkit (ADT) has been removed
+            because its functionality almost completely overlapped with the
+            <ulink url='&YOCTO_DOCS_SDK_URL;#sdk-using-the-standard-sdk'>standard SDK</ulink>
+            and the
+            <ulink url='&YOCTO_DOCS_SDK_URL;#sdk-extensible'>extensible SDK</ulink>.
+            For information on these SDKs and how to build and use them, see the
+            <ulink url='&YOCTO_DOCS_SDK_URL;'>Yocto Project Application Development and the Extensible Software Development Kit (eSDK)</ulink>
+            manual.
+            <note>
+                The Yocto Project Eclipse IDE Plug-in is still supported and
+                is not affected by this change.
+            </note>
+        </para>
+    </section>
+
+    <section id='migration-2.1-poky-reference-distribution-changes'>
+        <title>Poky Reference Distribution Changes</title>
+
+        <para>
+            The following changes have been made for the Poky distribution:
+            <itemizedlist>
+                <listitem><para>
+                    The <filename>meta-yocto</filename> layer has been renamed
+                    to <filename>meta-poky</filename> to better match its
+                    purpose, which is to provide the Poky reference
+                    distribution.
+                    The <filename>meta-yocto-bsp</filename> layer retains its
+                    original name since it provides reference machines for
+                    the Yocto Project and it is otherwise unrelated to Poky.
+                    References to <filename>meta-yocto</filename> in your
+                    <filename>conf/bblayers.conf</filename> should
+                    automatically be updated, so you should not need to change
+                    anything unless you are relying on this naming elsewhere.
+                    </para></listitem>
+                <listitem><para>
+                    The
+                    <link linkend='ref-classes-uninative'><filename>uninative</filename></link>
+                    class is now enabled by default in Poky.
+                    This class attempts to isolate the build system from the
+                    host distribution's C library and makes re-use of native
+                    shared state artifacts across different host distributions
+                    practical.
+                    With this class enabled, a tarball containing a pre-built
+                    C library is downloaded at the start of the build.</para>
+
+                    <para>The <filename>uninative</filename> class is enabled
+                    through the
+                    <filename>meta/conf/distro/include/yocto-uninative.inc</filename>
+                    file, which for those not using the Poky distribution, can
+                    include to easily enable the same functionality.</para>
+
+                    <para>Alternatively, if you wish to build your own
+                    <filename>uninative</filename> tarball, you can do so by
+                    building the <filename>uninative-tarball</filename> recipe,
+                    making it available to your build machines
+                    (e.g. over HTTP/HTTPS) and setting a similar configuration
+                    as the one set by <filename>yocto-uninative.inc</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    Static library generation, for most cases, is now disabled
+                    by default in the Poky distribution.
+                    Disabling this generation saves some build time as well
+                    as the size used for build output artifacts.</para>
+
+                    <para>Disabling this library generation is accomplished
+                    through a
+                    <filename>meta/conf/distro/include/no-static-libs.inc</filename>,
+                    which for those not using the Poky distribution can
+                    easily include to enable the same functionality.</para>
+
+                    <para>Any recipe that needs to opt-out of having the
+                    "--disable-static" option specified on the configure
+                    command line either because it is not a supported option
+                    for the configure script or because static libraries are
+                    needed should set the following variable:
+                    <literallayout class='monospaced'>
+     DISABLE_STATIC = ""
+                    </literallayout>
+                    </para></listitem>
+                <listitem><para>
+                    The separate <filename>poky-tiny</filename> distribution
+                    now uses the musl C library instead of a heavily pared
+                    down <filename>glibc</filename>.
+                    Using musl results in a smaller
+                    distribution and facilitates much greater maintainability
+                    because musl is designed to have a small footprint.</para>
+
+                    <para>If you have used <filename>poky-tiny</filename> and
+                    have customized the <filename>glibc</filename>
+                    configuration you will need to redo those customizations
+                    with musl when upgrading to the new release.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.1-packaging-changes'>
+        <title>Packaging Changes</title>
+
+        <para>
+            The following changes have been made to packaging:
+            <itemizedlist>
+                <listitem><para>
+                    The <filename>runuser</filename> and
+                    <filename>mountpoint</filename> binaries, which were
+                    previously in the main <filename>util-linux</filename>
+                    package, have been split out into the
+                    <filename>util-linux-runuser</filename> and
+                    <filename>util-linux-mountpoint</filename> packages,
+                    respectively.
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>python-elementtree</filename> package has
+                    been merged into the <filename>python-xml</filename>
+                    package.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.1-tuning-file-changes'>
+        <title>Tuning File Changes</title>
+
+        <para>
+            The following changes have been made to the tuning files:
+            <itemizedlist>
+                <listitem><para>
+                    The "no-thumb-interwork" tuning feature has been dropped
+                    from the ARM tune include files.
+                    Because interworking is required for ARM EABI, attempting
+                    to disable it through a tuning feature no longer makes
+                    sense.
+                    <note>
+                        Support for ARM OABI was deprecated in gcc 4.7.
+                    </note>
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>tune-cortexm*.inc</filename> and
+                    <filename>tune-cortexr4.inc</filename> files have been
+                    removed because they are poorly tested.
+                    Until the OpenEmbedded build system officially gains
+                    support for CPUs without an MMU, these tuning files would
+                    probably be better maintained in a separate layer
+                    if needed.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.1-supporting-gobject-introspection'>
+        <title>Supporting GObject Introspection</title>
+
+        <para>
+            This release supports generation of GLib Introspective
+            Repository (GIR) files through GObject introspection, which is
+            the standard mechanism for accessing GObject-based software from
+            runtime environments.
+            You can enable, disable, and test the generation of this data.
+            See the
+            "<ulink url='&YOCTO_DOCS_DEV_URL;#enabling-gobject-introspection-support'>Enabling GObject Introspection Support</ulink>"
+            section in the Yocto Project Development Tasks Manual
+            for more information.
+        </para>
+    </section>
+
+    <section id='migration-2.1-miscellaneous-changes'>
+        <title>Miscellaneous Changes</title>
+
+        <para>
+            These additional changes exist:
+            <itemizedlist>
+                <listitem><para>
+                    The minimum Git version has been increased to 1.8.3.1.
+                    If your host distribution does not provide a sufficiently
+                    recent version, you can install the buildtools, which
+                    will provide it.
+                    See the
+                    "<link linkend='required-git-tar-python-and-gcc-versions'>Required Git, tar, Python and gcc Versions</link>"
+                    section for more information on the buildtools tarball.
+                    </para></listitem>
+                <listitem><para>
+                    The buggy and incomplete support for the RPM version 4
+                    package manager has been removed.
+                    The well-tested and maintained support for RPM version 5
+                    remains.
+                    </para></listitem>
+                <listitem><para>
+                    Previously, the following list of packages were removed
+                    if package-management was not in
+                    <link linkend='var-IMAGE_FEATURES'><filename>IMAGE_FEATURES</filename></link>,
+                    regardless of any dependencies:
+                    <literallayout class='monospaced'>
+     update-rc.d
+     base-passwd
+     shadow
+     update-alternatives
+     run-postinsts
+                    </literallayout>
+                    With the Yocto Project 2.1 release, these packages are only
+                    removed if "read-only-rootfs" is in
+                    <filename>IMAGE_FEATURES</filename>, since they might
+                    still be needed for a read-write image even in the absence
+                    of a package manager (e.g. if users need to be added,
+                    modified, or removed at runtime).
+                    </para></listitem>
+                <listitem><para>
+                    The
+                    <ulink url='&YOCTO_DOCS_SDK_URL;#sdk-devtool-use-devtool-modify-to-modify-the-source-of-an-existing-component'><filename>devtool modify</filename></ulink>
+                    command now defaults to extracting the source since that
+                    is most commonly expected.
+                    The "-x" or "--extract" options are now no-ops.
+                    If you wish to provide your own existing source tree, you
+                    will now need to specify either the "-n" or
+                    "--no-extract" options when running
+                    <filename>devtool modify</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    If the formfactor for a machine is either not supplied
+                    or does not specify whether a keyboard is attached, then
+                    the default is to assume a keyboard is attached rather
+                    than assume no keyboard.
+                    This change primarily affects the Sato UI.
+                   </para></listitem>
+                <listitem><para>
+                    The <filename>.debug</filename> directory packaging is
+                    now automatic.
+                    If your recipe builds software that installs binaries into
+                    directories other than the standard ones, you no longer
+                    need to take care of setting
+                    <filename>FILES_${PN}-dbg</filename> to pick up the
+                    resulting <filename>.debug</filename> directories as these
+                    directories are automatically found and added.
+                    </para></listitem>
+                <listitem><para>
+                    Inaccurate disk and CPU percentage data has been dropped
+                    from <filename>buildstats</filename> output.
+                    This data has been replaced with
+                    <filename>getrusage()</filename> data and corrected IO
+                    statistics.
+                    You will probably need to update any custom code that reads
+                    the <filename>buildstats</filename> data.
+                    </para></listitem>
+                <listitem><para>
+                    The
+                    <filename>meta/conf/distro/include/package_regex.inc</filename>
+                    is now deprecated.
+                    The contents of this file have been moved to individual
+                    recipes.
+                    <note><title>Tip</title>
+                        Because this file will likely be removed in a future
+                        Yocto Project release, it is suggested that you remove
+                        any references to the file that might be in your
+                        configuration.
+                    </note>
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>v86d/uvesafb</filename> has been removed from
+                    the <filename>genericx86</filename> and
+                    <filename>genericx86-64</filename> reference machines,
+                    which are provided by the
+                    <filename>meta-yocto-bsp</filename> layer.
+                    Most modern x86 boards do not rely on this file and it only
+                    adds kernel error messages during startup.
+                    If you do still need to support
+                    <filename>uvesafb</filename>, you can
+                    simply add <filename>v86d</filename> to your image.
+                    </para></listitem>
+                <listitem><para>
+                     Build sysroot paths are now removed from debug symbol
+                     files.
+                     Removing these paths means that remote GDB using an
+                     unstripped build system sysroot will no longer work
+                     (although this was never documented to work).
+                     The supported method to accomplish something similar is
+                     to set <filename>IMAGE_GEN_DEBUGFS</filename> to "1",
+                     which will generate a companion debug image
+                     containing unstripped binaries and associated debug
+                     sources alongside the image.
+                     </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+</section>
+
+<section id='moving-to-the-yocto-project-2.2-release'>
+    <title>Moving to the Yocto Project 2.2 Release</title>
+
+    <para>
+        This section provides migration information for moving to the
+        Yocto Project 2.2 Release from the prior release.
+    </para>
+
+    <section id='migration-2.2-minimum-kernel-version'>
+        <title>Minimum Kernel Version</title>
+
+        <para>
+            The minimum kernel version for the target system and for SDK
+            is now 3.2.0, due to the upgrade
+            to <filename>glibc 2.24</filename>.
+            Specifically, for AArch64-based targets the version is
+            3.14.
+            For Nios II-based targets, the minimum kernel version is 3.19.
+            <note>
+                For x86 and x86_64, you can reset
+                <link linkend='var-OLDEST_KERNEL'><filename>OLDEST_KERNEL</filename></link>
+                to anything down to 2.6.32 if desired.
+            </note>
+        </para>
+    </section>
+
+    <section id='migration-2.2-staging-directories-in-sysroot-simplified'>
+        <title>Staging Directories in Sysroot Has Been Simplified</title>
+
+        <para>
+            The way directories are staged in sysroot has been simplified and
+            introduces the new
+            <link linkend='var-SYSROOT_DIRS'><filename>SYSROOT_DIRS</filename></link>,
+            <link linkend='var-SYSROOT_DIRS_NATIVE'><filename>SYSROOT_DIRS_NATIVE</filename></link>,
+            and
+            <link linkend='var-SYSROOT_DIRS_BLACKLIST'><filename>SYSROOT_DIRS_BLACKLIST</filename></link>.
+            See the
+            <ulink url='http://lists.openembedded.org/pipermail/openembedded-core/2016-May/121365.html'>v2 patch series on the OE-Core Mailing List</ulink>
+            for additional information.
+        </para>
+    </section>
+
+    <section id='migration-2.2-removal-of-old-images-from-tmp-deploy-now-enabled'>
+        <title>Removal of Old Images and Other Files in <filename>tmp/deploy</filename> Now Enabled</title>
+
+        <para>
+            Removal of old images and other files in
+            <filename>tmp/deploy/</filename> is now enabled by default due
+            to a new staging method used for those files.
+            As a result of this change, the
+            <filename>RM_OLD_IMAGE</filename> variable is now redundant.
+        </para>
+    </section>
+
+    <section id='migration-2.2-python-changes'>
+        <title>Python Changes</title>
+
+        <para>
+            The following changes for Python occurred:
+        </para>
+
+        <section id='migration-2.2-bitbake-now-requires-python-3.4'>
+            <title>BitBake Now Requires Python 3.4+</title>
+
+            <para>
+                BitBake requires Python 3.4 or greater.
+            </para>
+        </section>
+
+        <section id='migration-2.2-utf-8-locale-required-on-build-host'>
+            <title>UTF-8 Locale Required on Build Host</title>
+
+            <para>
+                A UTF-8 locale is required on the build host due to Python 3.
+                Since C.UTF-8 is not a standard, the default is en_US.UTF-8.
+            </para>
+        </section>
+
+        <section id='migration-2.2-metadata-now-must-use-python-3-syntax'>
+            <title>Metadata Must Now Use Python 3 Syntax</title>
+
+            <para>
+                The metadata is now required to use Python 3 syntax.
+                For help preparing metadata, see any of the many Python 3 porting
+                guides available.
+                Alternatively, you can reference the conversion commits for Bitbake
+                and you can use
+                <link linkend='oe-core'>OE-Core</link> as a guide for changes.
+                Following are particular areas of interest:
+                <literallayout class='monospaced'>
+     * subprocess command-line pipes needing locale decoding
+     * the syntax for octal values changed
+     * the <filename>iter*()</filename> functions changed name
+     * iterators now return views, not lists
+     * changed names for Python modules
+                </literallayout>
+            </para>
+        </section>
+
+        <section id='migration-2.2-target-python-recipes-switched-to-python-3'>
+            <title>Target Python Recipes Switched to Python 3</title>
+
+            <para>
+                Most target Python recipes have now been switched to Python 3.
+                Unfortunately, systems using RPM as a package manager and
+                providing online package-manager support through SMART still
+                require Python 2.
+                <note>
+                    Python 2 and recipes that use it can still be built for the
+                    target as with previous versions.
+                </note>
+            </para>
+        </section>
+
+        <section id='migration-2.2-buildtools-tarball-includes-python-3'>
+            <title><filename>buildtools-tarball</filename> Includes Python 3</title>
+
+            <para>
+                <filename>buildtools-tarball</filename> now includes Python 3.
+            </para>
+        </section>
+    </section>
+
+    <section id='migration-2.2-uclibc-replaced-by-musl'>
+        <title>uClibc Replaced by musl</title>
+
+        <para>
+            uClibc has been removed in favor of musl.
+            Musl has matured, is better maintained, and is compatible with a
+            wider range of applications as compared to uClibc.
+        </para>
+    </section>
+
+    <section id='migration-2.2-B-no-longer-default-working-directory-for-tasks'>
+        <title><filename>${B}</filename> No Longer Default Working Directory for Tasks</title>
+
+        <para>
+            <filename>${</filename><link linkend='var-B'><filename>B</filename></link><filename>}</filename>
+            is no longer the default working directory for tasks.
+            Consequently, any custom tasks you define now need to either
+            have the
+            <filename>[</filename><ulink url='&YOCTO_DOCS_BB_URL;#variable-flags'><filename>dirs</filename></ulink><filename>]</filename> flag set, or the task needs to change into the
+            appropriate working directory manually (e.g using
+            <filename>cd</filename> for a shell task).
+            <note>
+                The preferred method is to use the
+                <filename>[dirs]</filename> flag.
+            </note>
+        </para>
+    </section>
+
+    <section id='migration-2.2-runqemu-ported-to-python'>
+        <title><filename>runqemu</filename> Ported to Python</title>
+
+        <para>
+            <filename>runqemu</filename> has been ported to Python and has
+            changed behavior in some cases.
+            Previous usage patterns continue to be supported.
+        </para>
+
+        <para>
+            The new <filename>runqemu</filename> is a Python script.
+            Machine knowledge is no longer hardcoded into
+            <filename>runqemu</filename>.
+            You can choose to use the <filename>qemuboot</filename>
+            configuration file to define the BSP's own arguments and to make
+            it bootable with <filename>runqemu</filename>.
+            If you use a configuration file, use the following form:
+            <literallayout class='monospaced'>
+     <replaceable>image-name</replaceable>-<replaceable>machine</replaceable>.qemuboot.conf
+            </literallayout>
+            The configuration file enables fine-grained tuning of options
+            passed to QEMU without the <filename>runqemu</filename> script
+            hard-coding any knowledge about different machines.
+            Using a configuration file is particularly convenient when trying
+            to use QEMU with machines other than the
+            <filename>qemu*</filename> machines in
+            <link linkend='oe-core'>OE-Core</link>.
+            The <filename>qemuboot.conf</filename> file is generated by the
+            <filename>qemuboot</filename>
+            class when the root filesystem is being build (i.e.
+            build rootfs).
+            QEMU boot arguments can be set in BSP's configuration file and
+            the <filename>qemuboot</filename> class will save them to
+            <filename>qemuboot.conf</filename>.
+        </para>
+
+
+        <para>
+            If you want to use <filename>runqemu</filename> without a
+            configuration file, use the following command form:
+            <literallayout class='monospaced'>
+     $ runqemu <replaceable>machine</replaceable> <replaceable>rootfs</replaceable> <replaceable>kernel</replaceable> [<replaceable>options</replaceable>]
+            </literallayout>
+            Supported <replaceable>machines</replaceable> are as follows:
+            <literallayout class='monospaced'>
+     qemuarm
+     qemuarm64
+     qemux86
+     qemux86-64
+     qemuppc
+     qemumips
+     qemumips64
+     qemumipsel
+     qemumips64el
+            </literallayout>
+            Consider the following example, which uses the
+            <filename>qemux86-64</filename> machine,
+            provides a root filesystem, provides an image, and uses
+            the <filename>nographic</filename> option:
+            <literallayout class='monospaced'>
+$ runqemu qemux86-64 tmp/deploy/images/qemux86-64/core-image-minimal-qemux86-64.ext4 tmp/deploy/images/qemux86-64/bzImage nographic
+            </literallayout>
+        </para>
+
+        <para>
+            Following is a list of variables that can be set in configuration
+            files such as <filename>bsp.conf</filename> to enable the BSP
+            to be booted by <filename>runqemu</filename>:
+            <note>
+                "QB" means "QEMU Boot".
+            </note>
+            <literallayout class='monospaced'>
+     QB_SYSTEM_NAME: QEMU name (e.g. "qemu-system-i386")
+     QB_OPT_APPEND: Options to append to QEMU (e.g. "-show-cursor")
+     QB_DEFAULT_KERNEL: Default kernel to boot (e.g. "bzImage")
+     QB_DEFAULT_FSTYPE: Default FSTYPE to boot (e.g. "ext4")
+     QB_MEM: Memory (e.g. "-m 512")
+     QB_MACHINE: QEMU machine (e.g. "-machine virt")
+     QB_CPU: QEMU cpu (e.g. "-cpu qemu32")
+     QB_CPU_KVM: Similar to QB_CPU except used for kvm support (e.g. "-cpu kvm64")
+     QB_KERNEL_CMDLINE_APPEND: Options to append to the kernel's -append
+                               option (e.g. "console=ttyS0 console=tty")
+     QB_DTB: QEMU dtb name
+     QB_AUDIO_DRV: QEMU audio driver (e.g. "alsa", set it when support audio)
+     QB_AUDIO_OPT: QEMU audio option (e.g. "-soundhw ac97,es1370"), which is used
+                   when QB_AUDIO_DRV is set.
+     QB_KERNEL_ROOT: Kernel's root (e.g. /dev/vda)
+     QB_TAP_OPT: Network option for 'tap' mode (e.g.
+                 "-netdev tap,id=net0,ifname=@TAP@,script=no,downscript=no -device virtio-net-device,netdev=net0").
+                  runqemu will replace "@TAP@" with the one that is used, such as tap0, tap1 ...
+     QB_SLIRP_OPT: Network option for SLIRP mode (e.g. "-netdev user,id=net0 -device virtio-net-device,netdev=net0")
+     QB_ROOTFS_OPT: Used as rootfs (e.g.
+                    "-drive id=disk0,file=@ROOTFS@,if=none,format=raw -device virtio-blk-device,drive=disk0").
+                    runqemu will replace "@ROOTFS@" with the one which is used, such as
+                    core-image-minimal-qemuarm64.ext4.
+     QB_SERIAL_OPT: Serial port (e.g. "-serial mon:stdio")
+     QB_TCPSERIAL_OPT: tcp serial port option (e.g.
+                       " -device virtio-serial-device -chardev socket,id=virtcon,port=@PORT@,host=127.0.0.1 -device      virtconsole,chardev=virtcon"
+                       runqemu will replace "@PORT@" with the port number which is used.
+            </literallayout>
+        </para>
+
+        <para>
+            To use <filename>runqemu</filename>, set
+            <link linkend='var-IMAGE_CLASSES'><filename>IMAGE_CLASSES</filename></link>
+            as follows and run <filename>runqemu</filename>:
+            <note>
+                For command-line syntax, use
+                <filename>runqemu help</filename>.
+            </note>
+            <literallayout class='monospaced'>
+     IMAGE_CLASSES += "qemuboot"
+            </literallayout>
+        </para>
+    </section>
+
+    <section id='migration-2.2-default-linker-hash-style-changed'>
+        <title>Default Linker Hash Style Changed</title>
+
+        <para>
+            The default linker hash style for <filename>gcc-cross</filename>
+            is now "sysv" in order to catch recipes that are building software
+            without using the OpenEmbedded
+            <link linkend='var-LDFLAGS'><filename>LDFLAGS</filename></link>.
+            This change could result in seeing some "No GNU_HASH in the elf
+            binary" QA issues when building such recipes.
+            You need to fix these recipes so that they use the expected
+            <filename>LDFLAGS</filename>.
+            Depending on how the software is built, the build system used by
+            the software (e.g. a Makefile) might need to be patched.
+            However, sometimes making this fix is as simple as adding the
+            following to the recipe:
+            <literallayout class='monospaced'>
+     TARGET_CC_ARCH += "${LDFLAGS}"
+            </literallayout>
+        </para>
+    </section>
+
+    <section id='migration-2.2-kernel-image-base-name-no-longer-uses-kernel-imagetype'>
+        <title><filename>KERNEL_IMAGE_BASE_NAME</filename> no Longer Uses <filename>KERNEL_IMAGETYPE</filename></title>
+
+        <para>
+            The
+            <filename>KERNEL_IMAGE_BASE_NAME</filename>
+            variable no longer uses the
+            <link linkend='var-KERNEL_IMAGETYPE'><filename>KERNEL_IMAGETYPE</filename></link>
+            variable to create the image's base name.
+            Because the OpenEmbedded build system can now build multiple kernel
+            image types, this part of the kernel image base name as been
+            removed leaving only the following:
+            <literallayout class='monospaced'>
+     KERNEL_IMAGE_BASE_NAME ?= "${PKGE}-${PKGV}-${PKGR}-${MACHINE}-${DATETIME}"
+            </literallayout>
+            If you have recipes or classes that use
+            <filename>KERNEL_IMAGE_BASE_NAME</filename> directly, you might
+            need to update the references to ensure they continue to work.
+        </para>
+    </section>
+
+    <section id='migration-2.2-bitbake-changes'>
+        <title>BitBake Changes</title>
+
+        <para>
+            The following changes took place for BitBake:
+            <itemizedlist>
+                <listitem><para>
+                    The "goggle" UI and standalone image-writer tool have
+                    been removed as they both require GTK+ 2.0 and
+                    were not being maintained.
+                    </para></listitem>
+                <listitem><para>
+                    The Perforce fetcher now supports
+                    <link linkend='var-SRCREV'><filename>SRCREV</filename></link>
+                    for specifying the source revision to use, be it
+                    <filename>${</filename><link linkend='var-AUTOREV'><filename>AUTOREV</filename></link><filename>}</filename>,
+                    changelist number, p4date, or label, in preference to
+                    separate
+                    <link linkend='var-SRC_URI'><filename>SRC_URI</filename></link>
+                    parameters to specify these.
+                    This change is more in-line with how the other fetchers
+                    work for source control systems.
+                    Recipes that fetch from Perforce will need to be updated
+                    to use <filename>SRCREV</filename> in place of specifying
+                    the source revision within
+                    <filename>SRC_URI</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    Some of BitBake's internal code structures for accessing
+                    the recipe cache needed to be changed to support the new
+                    multi-configuration functionality.
+                    These changes will affect external tools that use BitBake's
+                    tinfoil module.
+                    For information on these changes, see the changes made to
+                    the scripts supplied with OpenEmbedded-Core:
+                    <ulink url='http://git.yoctoproject.org/cgit/cgit.cgi/poky/commit/?id=189371f8393971d00bca0fceffd67cc07784f6ee'>1</ulink>
+                    and
+                    <ulink url='http://git.yoctoproject.org/cgit/cgit.cgi/poky/commit/?id=4a5aa7ea4d07c2c90a1654b174873abb018acc67'>2</ulink>.
+                    </para></listitem>
+                <listitem><para>
+                    The task management code has been rewritten to avoid using
+                    ID indirection in order to improve performance.
+                    This change is unlikely to cause any problems for most
+                    users.
+                    However, the setscene verification function as pointed to
+                    by <filename>BB_SETSCENE_VERIFY_FUNCTION</filename>
+                    needed to change signature.
+                    Consequently, a new variable named
+                    <filename>BB_SETSCENE_VERIFY_FUNCTION2</filename>
+                    has been added allowing multiple versions of BitBake
+                    to work with suitably written metadata, which includes
+                    OpenEmbedded-Core and Poky.
+                    Anyone with custom BitBake task scheduler code might also
+                    need to update the code to handle the new structure.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.2-swabber-has-been-removed'>
+        <title>Swabber has Been Removed</title>
+
+        <para>
+            Swabber, a tool that was intended to detect host contamination in
+            the build process, has been removed, as it has been unmaintained
+            and unused for some time and was never particularly effective.
+            The OpenEmbedded build system has since incorporated a number of
+            mechanisms including enhanced QA checks that mean that there is
+            less of a need for such a tool.
+        </para>
+    </section>
+
+    <section id='migration-2.2-removed-recipes'>
+        <title>Removed Recipes</title>
+
+        <para>
+            The following recipes have been removed:
+            <itemizedlist>
+                <listitem><para>
+                    <filename>augeas</filename>:
+                    No longer needed and has been moved to
+                    <filename>meta-oe</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>directfb</filename>:
+                    Unmaintained and has been moved to
+                    <filename>meta-oe</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>gcc</filename>:
+                    Removed 4.9 version.
+                    Versions 5.4 and 6.2 are still present.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>gnome-doc-utils</filename>:
+                    No longer needed.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>gtk-doc-stub</filename>:
+                    Replaced by <filename>gtk-doc</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>gtk-engines</filename>:
+                    No longer needed and has been moved to
+                    <filename>meta-gnome</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>gtk-sato-engine</filename>:
+                    Became obsolete.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>libglade</filename>:
+                    No longer needed and has been moved to
+                    <filename>meta-oe</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>libmad</filename>:
+                    Unmaintained and functionally replaced by
+                    <filename>libmpg123</filename>.
+                    <filename>libmad</filename> has been moved to
+                    <filename>meta-oe</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>libowl</filename>:
+                    Became obsolete.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>libxsettings-client</filename>:
+                    No longer needed.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>oh-puzzles</filename>:
+                    Functionally replaced by
+                    <filename>puzzles</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>oprofileui</filename>:
+                    Became obsolete.
+                    OProfile has been largely supplanted by perf.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>packagegroup-core-directfb.bb</filename>:
+                    Removed.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>core-image-directfb.bb</filename>:
+                    Removed.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>pointercal</filename>:
+                    No longer needed and has been moved to
+                    <filename>meta-oe</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>python-imaging</filename>:
+                    No longer needed and moved to
+                    <filename>meta-python</filename>
+                    </para></listitem>
+                <listitem><para>
+                    <filename>python-pyrex</filename>:
+                    No longer needed and moved to
+                    <filename>meta-python</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>sato-icon-theme</filename>:
+                    Became obsolete.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>swabber-native</filename>:
+                    Swabber has been removed.
+                    See the
+                    <link linkend='migration-2.2-swabber-has-been-removed'>entry on Swabber</link>.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>tslib</filename>:
+                    No longer needed and has been moved to
+                    <filename>meta-oe</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>uclibc</filename>:
+                    Removed in favor of musl.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>xtscal</filename>:
+                    No longer needed and moved to
+                    <filename>meta-oe</filename>
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.2-removed-classes'>
+        <title>Removed Classes</title>
+
+        <para>
+            The following classes have been removed:
+            <itemizedlist>
+                <listitem><para>
+                    <filename>distutils-native-base</filename>:
+                    No longer needed.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>distutils3-native-base</filename>:
+                    No longer needed.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>sdl</filename>:
+                    Only set
+                    <link linkend='var-DEPENDS'><filename>DEPENDS</filename></link>
+                    and
+                    <link linkend='var-SECTION'><filename>SECTION</filename></link>,
+                    which are better set within the recipe instead.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>sip</filename>:
+                    Mostly unused.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>swabber</filename>:
+                    See the
+                    <link linkend='migration-2.2-swabber-has-been-removed'>entry on Swabber</link>.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.2-minor-packaging-changes'>
+        <title>Minor Packaging Changes</title>
+
+        <para>
+            The following minor packaging changes have occurred:
+            <itemizedlist>
+                <listitem><para>
+                    <filename>grub</filename>:
+                    Split <filename>grub-editenv</filename> into its own
+                    package.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>systemd</filename>:
+                    Split container and vm related units into a new package,
+                    systemd-container.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>util-linux</filename>:
+                    Moved <filename>prlimit</filename> to a separate
+                    <filename>util-linux-prlimit</filename> package.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.2-miscellaneous-changes'>
+        <title>Miscellaneous Changes</title>
+
+        <para>
+            The following miscellaneous changes have occurred:
+            <itemizedlist>
+                <listitem><para>
+                    <filename>package_regex.inc</filename>:
+                    Removed because the definitions
+                    <filename>package_regex.inc</filename> previously contained
+                    have been moved to their respective recipes.
+                    </para></listitem>
+                <listitem><para>
+                    Both <filename>devtool add</filename> and
+                    <filename>recipetool create</filename> now use a fixed
+                    <link linkend='var-SRCREV'><filename>SRCREV</filename></link>
+                    by default when fetching from a Git repository.
+                    You can override this in either case to use
+                    <filename>${</filename><link linkend='var-AUTOREV'><filename>AUTOREV</filename></link><filename>}</filename>
+                    instead by using the <filename>-a</filename> or
+                    <filename>&dash;&dash;autorev</filename> command-line
+                    option
+                    </para></listitem>
+                <listitem><para>
+                    <filename>distcc</filename>:
+                    GTK+ UI is now disabled by default.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>packagegroup-core-tools-testapps</filename>:
+                    Removed Piglit.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>image.bbclass</filename>:
+                    Renamed COMPRESS(ION) to CONVERSION.
+                    This change means that
+                    <filename>COMPRESSIONTYPES</filename>,
+                    <filename>COMPRESS_DEPENDS</filename> and
+                    <filename>COMPRESS_CMD</filename> are deprecated in favor
+                    of <filename>CONVERSIONTYPES</filename>,
+                    <filename>CONVERSION_DEPENDS</filename> and
+                    <filename>CONVERSION_CMD</filename>.
+                    The <filename>COMPRESS*</filename> variable names will
+                    still work in the 2.2 release but metadata that does not
+                    need to be backwards-compatible should be changed to
+                    use the new names as the <filename>COMPRESS*</filename>
+                    ones will be removed in a future release.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>gtk-doc</filename>:
+                    A full version of <filename>gtk-doc</filename> is now
+                    made available.
+                    However, some old software might not be capable of using
+                    the current version of <filename>gtk-doc</filename>
+                    to build documentation.
+                    You need to change recipes that build such software so that
+                    they explicitly disable building documentation with
+                    <filename>gtk-doc</filename>.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+</section>
+
+<section id='moving-to-the-yocto-project-2.3-release'>
+    <title>Moving to the Yocto Project 2.3 Release</title>
+
+    <para>
+        This section provides migration information for moving to the
+        Yocto Project 2.3 Release from the prior release.
+    </para>
+
+    <section id='migration-2.3-recipe-specific-sysroots'>
+        <title>Recipe-specific Sysroots</title>
+
+        <para>
+            The OpenEmbedded build system now uses one sysroot per
+            recipe to resolve long-standing issues with configuration
+            script auto-detection of undeclared dependencies.
+            Consequently, you might find that some of your previously
+            written custom recipes are missing declared dependencies,
+            particularly those dependencies that are incidentally built
+            earlier in a typical build process and thus are already likely
+            to be present in the shared sysroot in previous releases.
+        </para>
+
+        <para>
+            Consider the following:
+            <itemizedlist>
+                <listitem><para>
+                    <emphasis>Declare Build-Time Dependencies:</emphasis>
+                    Because of this new feature, you must explicitly
+                    declare all build-time dependencies for your recipe.
+                    If you do not declare these dependencies, they are not
+                    populated into the sysroot for the recipe.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Specify Pre-Installation and Post-Installation
+                    Native Tool Dependencies:</emphasis>
+                    You must specifically specify any special native tool
+                    dependencies of <filename>pkg_preinst</filename> and
+                    <filename>pkg_postinst</filename> scripts by using the
+                    <link linkend='var-PACKAGE_WRITE_DEPS'><filename>PACKAGE_WRITE_DEPS</filename></link>
+                    variable.
+                    Specifying these dependencies ensures that these tools
+                    are available if these scripts need to be run on the
+                    build host during the
+                    <link linkend='ref-tasks-rootfs'><filename>do_rootfs</filename></link>
+                    task.</para>
+
+                    <para>As an example, see the <filename>dbus</filename>
+                    recipe.
+                    You will see that this recipe has a
+                    <filename>pkg_postinst</filename> that calls
+                    <filename>systemctl</filename> if "systemd" is in
+                    <link linkend='var-DISTRO_FEATURES'><filename>DISTRO_FEATURES</filename></link>.
+                    In the example,
+                    <filename>systemd-systemctl-native</filename> is added to
+                    <filename>PACKAGE_WRITE_DEPS</filename>, which is also
+                    conditional on "systemd" being in
+                    <filename>DISTRO_FEATURES</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Examine Recipes that Use
+                    <filename>SSTATEPOSTINSTFUNCS</filename>:</emphasis>
+                    You need to examine any recipe that uses
+                    <filename>SSTATEPOSTINSTFUNCS</filename> and determine
+                    steps to take.</para>
+
+                    <para>Functions added to
+                    <filename>SSTATEPOSTINSTFUNCS</filename> are still
+                    called as they were in previous Yocto Project releases.
+                    However, since a separate sysroot is now being populated
+                    for every recipe and if existing functions being called
+                    through <filename>SSTATEPOSTINSTFUNCS</filename> are
+                    doing relocation, then you will need to change these
+                    to use a post-installation script that is installed by a
+                    function added to
+                    <link linkend='var-SYSROOT_PREPROCESS_FUNCS'><filename>SYSROOT_PREPROCESS_FUNCS</filename></link>.
+                    </para>
+
+                    <para>For an example, see the
+                    <filename>pixbufcache</filename> class in
+                    <filename>meta/classes/</filename> in the Yocto Project
+                    <ulink url='&YOCTO_DOCS_OM_URL;#source-repositories'>Source Repositories</ulink>.
+                    <note>
+                        The <filename>SSTATEPOSTINSTFUNCS</filename> variable
+                        itself is now deprecated in favor of the
+                        <filename>do_populate_sysroot[postfuncs]</filename>
+                        task.
+                        Consequently, if you do still have any function or
+                        functions that need to be called after the sysroot
+                        component is created for a recipe, then you would be
+                        well advised to take steps to use a post installation
+                        script as described previously.
+                        Taking these steps prepares your code for when
+                        <filename>SSTATEPOSTINSTFUNCS</filename> is
+                        removed in a future Yocto Project release.
+                    </note>
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Specify the Sysroot when Using Certain
+                    External Scripts:</emphasis>
+                    Because the shared sysroot is now gone, the scripts
+                    <filename>oe-find-native-sysroot</filename> and
+                    <filename>oe-run-native</filename> have been changed such
+                    that you need to specify which recipe's
+                    <link linkend='var-STAGING_DIR_NATIVE'><filename>STAGING_DIR_NATIVE</filename></link>
+                    is used.
+                    </para></listitem>
+            </itemizedlist>
+            <note>
+                You can find more information on how recipe-specific sysroots
+                work in the
+                "<link linkend='ref-classes-staging'><filename>staging.bbclass</filename></link>"
+                section.
+            </note>
+        </para>
+    </section>
+
+    <section id='migration-2.3-path-variable'>
+        <title><filename>PATH</filename> Variable</title>
+
+        <para>
+            Within the environment used to run build tasks, the environment
+            variable <filename>PATH</filename> is now sanitized such that
+            the normal native binary paths
+            (<filename>/bin</filename>, <filename>/sbin</filename>,
+            <filename>/usr/bin</filename> and so forth) are
+            removed and a directory containing symbolic links linking only
+            to the binaries from the host mentioned in the
+            <link linkend='var-HOSTTOOLS'><filename>HOSTTOOLS</filename></link>
+            and
+            <link linkend='var-HOSTTOOLS_NONFATAL'><filename>HOSTTOOLS_NONFATAL</filename></link>
+            variables is added to <filename>PATH</filename>.
+        </para>
+
+        <para>
+            Consequently, any native binaries provided by the host that you
+            need to call needs to be in one of these two variables at
+            the configuration level.
+        </para>
+
+        <para>
+            Alternatively, you can add a native recipe (i.e.
+            <filename>-native</filename>) that provides the
+            binary to the recipe's
+            <link linkend='var-DEPENDS'><filename>DEPENDS</filename></link>
+            value.
+            <note>
+                <filename>PATH</filename> is not sanitized in the same way
+                within <filename>devshell</filename>.
+                If it were, you would have difficulty running host tools for
+                development and debugging within the shell.
+            </note>
+        </para>
+    </section>
+
+    <section id='migration-2.3-scripts'>
+        <title>Changes to Scripts</title>
+
+        <para>
+            The following changes to scripts took place:
+            <itemizedlist>
+                <listitem><para>
+                    <emphasis><filename>oe-find-native-sysroot</filename>:</emphasis>
+                    The usage for the
+                    <filename>oe-find-native-sysroot</filename> script has
+                    changed to the following:
+                    <literallayout class='monospaced'>
+     $ . oe-find-native-sysroot <replaceable>recipe</replaceable>
+                    </literallayout>
+                    You must now supply a recipe for
+                    <replaceable>recipe</replaceable> as part of the command.
+                    Prior to the Yocto Project &DISTRO; release, it was not
+                    necessary to provide the script with the command.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>oe-run-native</filename>:</emphasis>
+                    The usage for the
+                    <filename>oe-run-native</filename> script has changed
+                    to the following:
+                    <literallayout class='monospaced'>
+     $ oe-run-native <replaceable>native_recipe</replaceable> <replaceable>tool</replaceable>
+                    </literallayout>
+                    You must supply the name of the native recipe and the tool
+                    you want to run as part of the command.
+                    Prior to the Yocto Project &DISTRO; release, it was not
+                    necessary to provide the native recipe with the command.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>cleanup-workdir</filename>:</emphasis>
+                    The <filename>cleanup-workdir</filename> script has been
+                    removed because the script was found to be deleting
+                    files it should not have, which lead to broken build
+                    trees.
+                    Rather than trying to delete portions of
+                    <link linkend='var-TMPDIR'><filename>TMPDIR</filename></link>
+                    and getting it wrong, it is recommended that you
+                    delete <filename>TMPDIR</filename> and have it restored
+                    from shared state (sstate) on subsequent builds.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>wipe-sysroot</filename>:</emphasis>
+                    The <filename>wipe-sysroot</filename> script has been
+                    removed as it is no longer needed with recipe-specific
+                    sysroots.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.3-functions'>
+        <title>Changes to Functions</title>
+
+        <para>
+            The previously deprecated
+            <filename>bb.data.getVar()</filename>,
+            <filename>bb.data.setVar()</filename>, and
+            related functions have been removed in favor of
+            <filename>d.getVar()</filename>,
+            <filename>d.setVar()</filename>, and so forth.
+        </para>
+
+        <para>
+            You need to fix any references to these old functions.
+        </para>
+    </section>
+
+    <section id='migration-2.3-bitbake-changes'>
+        <title>BitBake Changes</title>
+
+        <para>
+            The following changes took place for BitBake:
+            <itemizedlist>
+                <listitem><para>
+                    <emphasis>BitBake's Graphical Dependency Explorer UI Replaced:</emphasis>
+                    BitBake's graphical dependency explorer UI
+                    <filename>depexp</filename> was replaced by
+                    <filename>taskexp</filename> ("Task Explorer"), which
+                    provides a graphical way of exploring the
+                    <filename>task-depends.dot</filename> file.
+                    The data presented by Task Explorer is much more
+                    accurate than the data that was presented by
+                    <filename>depexp</filename>.
+                    Being able to visualize the data is an often requested
+                    feature as standard <filename>*.dot</filename> file
+                    viewers cannot usual cope with the size of
+                    the <filename>task-depends.dot</filename> file.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>BitBake "-g" Output Changes:</emphasis>
+                    The <filename>package-depends.dot</filename> and
+                    <filename>pn-depends.dot</filename> files as previously
+                    generated using the <filename>bitbake -g</filename> command
+                    have been removed.
+                    A <filename>recipe-depends.dot</filename> file
+                    is now generated as a collapsed version of
+                    <filename>task-depends.dot</filename> instead.
+                    </para>
+
+                    <para>The reason for this change is because
+                    <filename>package-depends.dot</filename> and
+                    <filename>pn-depends.dot</filename> largely date back
+                    to a time before task-based execution and do not take
+                    into account task-level dependencies between recipes,
+                    which could be misleading.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Mirror Variable Splitting Changes:</emphasis>
+                    Mirror variables including
+                    <link linkend='var-MIRRORS'><filename>MIRRORS</filename></link>,
+                    <link linkend='var-PREMIRRORS'><filename>PREMIRRORS</filename></link>,
+                    and
+                    <link linkend='var-SSTATE_MIRRORS'><filename>SSTATE_MIRRORS</filename></link>
+                    can now separate values entirely with spaces.
+                    Consequently, you no longer need "\\n".
+                    BitBake looks for pairs of values, which simplifies usage.
+                    There should be no change required to existing mirror
+                    variable values themselves.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>The Subversion (SVN) Fetcher Uses an "ssh" Parameter and Not an "rsh" Parameter:</emphasis>
+                    The SVN fetcher now takes an "ssh" parameter instead of an
+                    "rsh" parameter.
+                    This new optional parameter is used when the "protocol"
+                    parameter is set to "svn+ssh".
+                    You can only use the new parameter to specify the
+                    <filename>ssh</filename> program used by SVN.
+                    The SVN fetcher passes the new parameter through the
+                    <filename>SVN_SSH</filename> environment variable during
+                    the
+                    <link linkend='ref-tasks-fetch'><filename>do_fetch</filename></link>
+                    task.</para>
+
+                    <para>See the
+                    "<ulink url='&YOCTO_DOCS_BB_URL;#svn-fetcher'>Subversion (SVN) Fetcher (svn://)</ulink>"
+                    section in the BitBake User Manual for additional
+                    information.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>BB_SETSCENE_VERIFY_FUNCTION</filename>
+                    and <filename>BB_SETSCENE_VERIFY_FUNCTION2</filename>
+                    Removed:</emphasis>
+                    Because the mechanism they were part of is no longer
+                    necessary with recipe-specific sysroots, the
+                    <filename>BB_SETSCENE_VERIFY_FUNCTION</filename> and
+                    <filename>BB_SETSCENE_VERIFY_FUNCTION2</filename>
+                    variables have been removed.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.3-absolute-symlinks'>
+        <title>Absolute Symbolic Links</title>
+
+        <para>
+            Absolute symbolic links (symlinks) within staged files are no
+            longer permitted and now trigger an error.
+            Any explicit creation of symlinks can use the
+            <filename>lnr</filename> script, which is a replacement for
+            <filename>ln -r</filename>.
+        </para>
+
+        <para>
+            If the build scripts in the software that the recipe is building
+            are creating a number of absolute symlinks that need to be
+            corrected, you can inherit
+            <filename>relative_symlinks</filename> within the recipe to turn
+            those absolute symlinks into relative symlinks.
+        </para>
+    </section>
+
+    <section id='migration-2.3-gplv2-and-gplv3-moves'>
+        <title>GPLv2 Versions of GPLv3 Recipes Moved</title>
+
+        <para>
+            Older GPLv2 versions of GPLv3 recipes have moved to a
+            separate <filename>meta-gplv2</filename> layer.
+        </para>
+
+        <para>
+            If you use
+            <link linkend='var-INCOMPATIBLE_LICENSE'><filename>INCOMPATIBLE_LICENSE</filename></link>
+            to exclude GPLv3 or set
+            <link linkend='var-PREFERRED_VERSION'><filename>PREFERRED_VERSION</filename></link>
+            to substitute a GPLv2 version of a GPLv3 recipe, then you must add
+            the <filename>meta-gplv2</filename> layer to your configuration.
+            <note>
+                You can find <filename>meta-gplv2</filename> layer in the
+                OpenEmbedded layer index at
+                <ulink url='https://layers.openembedded.org/layerindex/branch/master/layer/meta-gplv2/'></ulink>.
+            </note>
+        </para>
+
+        <para>
+            These relocated GPLv2 recipes do not receive the same level of
+            maintenance as other core recipes.
+            The recipes do not get security fixes and upstream no longer
+            maintains them.
+            In fact, the upstream community is actively hostile towards people
+            that use the old versions of the recipes.
+            Moving these recipes into a separate layer both makes the different
+            needs of the recipes clearer and clearly identifies the number of
+            these recipes.
+            <note>
+                The long-term solution might be to move to BSD-licensed
+                replacements of the GPLv3 components for those that need to
+                exclude GPLv3-licensed components from the target system.
+                This solution will be investigated for future Yocto
+                Project releases.
+            </note>
+        </para>
+    </section>
+
+    <section id='migration-2.3-package-management-changes'>
+        <title>Package Management Changes</title>
+
+        <para>
+            The following package management changes took place:
+            <itemizedlist>
+                <listitem><para>
+                    Smart package manager is replaced by DNF package manager.
+                    Smart has become unmaintained upstream, is not ported
+                    to Python 3.x.
+                    Consequently, Smart needed to be replaced.
+                    DNF is the only feasible candidate.</para>
+                    <para>The change in functionality is that the on-target
+                    runtime package management from remote package feeds is
+                    now done with a different tool that has a
+                    different set of command-line options.
+                    If you have scripts that call the
+                    tool directly, or use its API, they need to be fixed.</para>
+                    <para>For more information, see the
+                    <ulink url='http://dnf.readthedocs.io/en/latest/'>DNF Documentation</ulink>.
+                    </para></listitem>
+                <listitem><para>
+                    Rpm 5.x is replaced with Rpm 4.x.
+                    This is done for two major reasons:
+                    <itemizedlist>
+                        <listitem><para>
+                            DNF is API-incompatible with Rpm 5.x and porting
+                            it and maintaining the port is non-trivial.
+                            </para></listitem>
+                        <listitem><para>
+                            Rpm 5.x itself has limited maintenance upstream,
+                            and the Yocto Project is one of the very few
+                            remaining users.
+                            </para></listitem>
+                    </itemizedlist>
+                    </para></listitem>
+                <listitem><para>
+                    Berkeley DB 6.x is removed and Berkeley DB 5.x becomes
+                    the default:
+                    <itemizedlist>
+                        <listitem><para>
+                            Version 6.x of Berkeley DB has largely been
+                            rejected by the open source community due to its
+                            AGPLv3 license.
+                            As a result, most mainstream open source projects
+                            that require DB are still developed and tested with
+                            DB 5.x.
+                            </para></listitem>
+                        <listitem><para>
+                            In OE-core, the only thing that was requiring
+                            DB 6.x was Rpm 5.x.
+                            Thus, no reason exists to continue carrying DB 6.x
+                            in OE-core.
+                            </para></listitem>
+                    </itemizedlist>
+                    </para></listitem>
+                <listitem><para>
+                    <filename>createrepo</filename> is replaced with
+                    <filename>createrepo_c</filename>.</para>
+                    <para><filename>createrepo_c</filename> is the current
+                    incarnation of the tool that generates remote repository
+                    metadata.
+                    It is written in C as compared to
+                    <filename>createrepo</filename>, which is written in
+                    Python.
+                    <filename>createrepo_c</filename> is faster and is
+                    maintained.
+                    </para></listitem>
+                <listitem><para>
+                    Architecture-independent RPM packages are "noarch"
+                    instead of "all".</para>
+                    <para>This change was made because too many places in
+                    DNF/RPM4 stack already make that assumption.
+                    Only the filenames and the architecture tag has changed.
+                    Nothing else has changed in OE-core system, particularly
+                    in the
+                    <link linkend='ref-classes-allarch'><filename>allarch.bbclass</filename></link>
+                    class.
+                    </para></listitem>
+                <listitem><para>
+                    Signing of remote package feeds using
+                    <filename>PACKAGE_FEED_SIGN</filename>
+                    is not currently supported.
+                    This issue will be fully addressed in a future
+                    Yocto Project release.
+                    See <ulink url='https://bugzilla.yoctoproject.org/show_bug.cgi?id=11209'>defect 11209</ulink>
+                    for more information on a solution to package feed
+                    signing with RPM in the Yocto Project 2.3 release.
+                    </para></listitem>
+                <listitem><para>
+                    OPKG now uses the libsolv backend for resolving package
+                    dependencies by default.
+                    This is vastly superior to OPKG's internal ad-hoc solver
+                    that was previously used.
+                    This change does have a small impact on disk (around
+                    500 KB) and memory footprint.
+                    <note>
+                        For further details on this change, see the
+                        <ulink url='http://git.yoctoproject.org/cgit/cgit.cgi/poky/commit/?
+id=f4d4f99cfbc2396e49c1613a7d237b9e57f06f81'>commit message</ulink>.
+                    </note>
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.3-removed-recipes'>
+        <title>Removed Recipes</title>
+
+        <para>
+            The following recipes have been removed:
+            <itemizedlist>
+                <listitem><para>
+                    <emphasis><filename>linux-yocto 4.8:</filename></emphasis>
+                    Version 4.8 has been removed.
+                    Versions 4.1 (LTSI), 4.4 (LTS), 4.9 (LTS/LTSI) and 4.10
+                    are now present.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>python-smartpm:</filename></emphasis>
+                    Functionally replaced by <filename>dnf</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>createrepo:</filename></emphasis>
+                    Replaced by the <filename>createrepo-c</filename> recipe.
+                    </para></listitem>
+                 <listitem><para>
+                    <emphasis><filename>rpmresolve:</filename></emphasis>
+                    No longer needed with the move to RPM 4 as RPM itself is
+                    used instead.
+                    </para></listitem>
+                 <listitem><para>
+                    <emphasis><filename>gstreamer:</filename></emphasis>
+                    Removed the GStreamer Git version recipes as they have
+                    been stale.
+                    <filename>1.10.</filename><replaceable>x</replaceable>
+                    recipes are still present.
+                    </para></listitem>
+                 <listitem><para>
+                    <emphasis><filename>alsa-conf-base:</filename></emphasis>
+                    Merged into <filename>alsa-conf</filename> since
+                    <filename>libasound</filename> depended on both.
+                    Essentially, no way existed to install only one of these.
+                    </para></listitem>
+                 <listitem><para>
+                    <emphasis><filename>tremor:</filename></emphasis>
+                    Moved to <filename>meta-multimedia</filename>.
+                    Fixed-integer Vorbis decoding is not
+                    needed by current hardware.
+                    Thus, GStreamer's ivorbis plugin has been disabled
+                    by default eliminating the need for the
+                    <filename>tremor</filename> recipe in
+                    <link linkend='oe-core'>OE-Core</link>.
+                    </para></listitem>
+                 <listitem><para>
+                    <emphasis><filename>gummiboot:</filename></emphasis>
+                    Replaced by <filename>systemd-boot</filename>.
+                    </para></listitem>
+           </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.3-wic-changes'>
+        <title>Wic Changes</title>
+
+        <para>
+            The following changes have been made to Wic:
+            <note>
+                For more information on Wic, see the
+                "<ulink url='&YOCTO_DOCS_DEV_URL;#creating-partitioned-images-using-wic'>Creating Partitioned Images Using Wic</ulink>"
+                section in the Yocto Project Development Tasks Manual.
+            </note>
+            <itemizedlist>
+                <listitem><para>
+                    <emphasis>Default Output Directory Changed:</emphasis>
+                    Wic's default output directory is now the current directory
+                    by default instead of the unusual
+                    <filename>/var/tmp/wic</filename>.</para>
+
+                    <para>The "-o" and "--outdir" options remain unchanged
+                    and are used to specify your preferred output directory
+                    if you do not want to use the default directory.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>fsimage Plug-in Removed:</emphasis>
+                    The Wic fsimage plugin has been removed as it duplicates
+                    functionality of the rawcopy plugin.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.3-qa-changes'>
+        <title>QA Changes</title>
+
+        <para>
+            The following QA checks have changed:
+            <itemizedlist>
+                <listitem><para>
+                    <emphasis><filename>unsafe-references-in-binaries</filename>:</emphasis>
+                    The <filename>unsafe-references-in-binaries</filename>
+                    QA check, which was disabled by default, has now been
+                    removed.
+                    This check was intended to detect binaries in
+                    <filename>/bin</filename> that link to libraries in
+                    <filename>/usr/lib</filename> and have the case where
+                    the user has <filename>/usr</filename> on a separate
+                    filesystem to <filename>/</filename>.</para>
+
+                    <para>The removed QA check was buggy.
+                    Additionally, <filename>/usr</filename> residing on a
+                    separate partition from <filename>/</filename> is now
+                    a rare configuration.
+                    Consequently,
+                    <filename>unsafe-references-in-binaries</filename> was
+                    removed.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>file-rdeps</filename>:</emphasis>
+                    The <filename>file-rdeps</filename> QA check is now an
+                    error by default instead of a warning.
+                    Because it is an error instead of a warning, you need to
+                    address missing runtime dependencies.</para>
+
+                    <para>For additional information, see the
+                    <link linkend='ref-classes-insane'><filename>insane</filename></link>
+                    class and the
+                    "<link linkend='qa-errors-and-warnings'>Errors and Warnings</link>"
+                    section.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.3-miscellaneous-changes'>
+        <title>Miscellaneous Changes</title>
+
+        <para>
+            The following miscellaneous changes have occurred:
+            <itemizedlist>
+                <listitem><para>
+                    In this release, a number of recipes have been changed to
+                    ignore the <filename>largefile</filename>
+                    <link linkend='var-DISTRO_FEATURES'><filename>DISTRO_FEATURES</filename></link>
+                    item, enabling large file support unconditionally.
+                    This feature has always been enabled by default.
+                    Disabling the feature has not been widely tested.
+                    <note>
+                        Future releases of the Yocto Project will remove
+                        entirely the ability to disable the
+                        <filename>largefile</filename> feature,
+                        which would make it unconditionally enabled everywhere.
+                    </note>
+                    </para></listitem>
+                <listitem><para>
+                    If the
+                    <link linkend='var-DISTRO_VERSION'><filename>DISTRO_VERSION</filename></link>
+                    value contains the value of the
+                    <link linkend='var-DATE'><filename>DATE</filename></link>
+                    variable, which is the default between Poky releases,
+                    the <filename>DATE</filename> value is explicitly excluded
+                    from <filename>/etc/issue</filename> and
+                    <filename>/etc/issue.net</filename>, which is displayed at
+                    the login prompt, in order to avoid conflicts with
+                    Multilib enabled.
+                    Regardless, the <filename>DATE</filename> value is
+                    inaccurate if the <filename>base-files</filename>
+                    recipe is restored from shared state (sstate) rather
+                    than rebuilt.</para>
+
+                    <para>If you need the build date recorded in
+                    <filename>/etc/issue*</filename> or anywhere else in your
+                    image, a better method is to define a post-processing
+                    function to do it and have the function called from
+                    <link linkend='var-ROOTFS_POSTPROCESS_COMMAND'><filename>ROOTFS_POSTPROCESS_COMMAND</filename></link>.
+                    Doing so ensures the value is always up-to-date with the
+                    created image.
+                    </para></listitem>
+                <listitem><para>
+                    Dropbear's <filename>init</filename> script now disables
+                    DSA host keys by default.
+                    This change is in line with the systemd service
+                    file, which supports RSA keys only, and with recent
+                    versions of OpenSSH, which deprecates DSA host keys.
+                    </para></listitem>
+                <listitem><para>
+                    The
+                    <link linkend='ref-classes-buildhistory'><filename>buildhistory</filename></link>
+                    class now correctly uses tabs as separators between all
+                    columns in <filename>installed-package-sizes.txt</filename>
+                    in order to aid import into other tools.
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>USE_LDCONFIG</filename> variable has been
+                    replaced with the "ldconfig"
+                    <filename>DISTRO_FEATURES</filename> feature.
+                    Distributions that previously set:
+                    <literallayout class='monospaced'>
+     USE_LDCONFIG = "0"
+                    </literallayout>
+                    should now instead use the following:
+                    <literallayout class='monospaced'>
+     DISTRO_FEATURES_BACKFILL_CONSIDERED_append = " ldconfig"
+                    </literallayout>
+                    </para></listitem>
+                <listitem><para>
+                    The default value of
+                    <link linkend='var-COPYLEFT_LICENSE_INCLUDE'><filename>COPYLEFT_LICENSE_INCLUDE</filename></link>
+                    now includes all versions of AGPL licenses in addition
+                    to GPL and LGPL.
+                    <note>
+                        The default list is not intended to be guaranteed
+                        as a complete safe list.
+                        You should seek legal advice based on what you are
+                        distributing if you are unsure.
+                    </note>
+                    </para></listitem>
+                <listitem><para>
+                    Kernel module packages are now suffixed with the kernel
+                    version in order to allow module packages from multiple
+                    kernel versions to co-exist on a target system.
+                    If you wish to return to the previous naming scheme
+                    that does not include the version suffix, use the
+                    following:
+                    <literallayout class='monospaced'>
+     KERNEL_MODULE_PACKAGE_SUFFIX to ""
+                    </literallayout>
+                    </para></listitem>
+                <listitem><para>
+                    Removal of <filename>libtool</filename>
+                    <filename>*.la</filename> files is now enabled by default.
+                    The <filename>*.la</filename> files are not actually
+                    needed on Linux and relocating them is an unnecessary
+                    burden.</para>
+
+                    <para>If you need to preserve these
+                    <filename>.la</filename> files (e.g. in a custom
+                    distribution), you must change
+                    <link linkend='var-INHERIT_DISTRO'><filename>INHERIT_DISTRO</filename></link>
+                    such that "remove-libtool" is not included in the value.
+                    </para></listitem>
+                <listitem><para>
+                    Extensible SDKs built for GCC 5+ now refuse to install on a
+                    distribution where the host GCC version is 4.8 or 4.9.
+                    This change resulted from the fact that the installation
+                    is known to fail due to the way the
+                    <filename>uninative</filename> shared state (sstate)
+                    package is built.
+                    See the
+                    <link linkend='ref-classes-uninative'><filename>uninative</filename></link>
+                    class for additional information.
+                    </para></listitem>
+                <listitem><para>
+                    All native and nativesdk recipes now use a separate
+                    <filename>DISTRO_FEATURES</filename> value instead of
+                    sharing the value used by recipes for the target, in order
+                    to avoid unnecessary rebuilds.</para>
+
+                    <para>The <filename>DISTRO_FEATURES</filename> for
+                    <filename>native</filename> recipes is
+                    <link linkend='var-DISTRO_FEATURES_NATIVE'><filename>DISTRO_FEATURES_NATIVE</filename></link>
+                    added to an intersection of
+                    <filename>DISTRO_FEATURES</filename> and
+                    <link linkend='var-DISTRO_FEATURES_FILTER_NATIVE'><filename>DISTRO_FEATURES_FILTER_NATIVE</filename></link>.
+                    </para>
+
+                    <para>For nativesdk recipes, the
+                    corresponding variables are
+                    <link linkend='var-DISTRO_FEATURES_NATIVESDK'><filename>DISTRO_FEATURES_NATIVESDK</filename></link>
+                    and
+                    <link linkend='var-DISTRO_FEATURES_FILTER_NATIVESDK'><filename>DISTRO_FEATURES_FILTER_NATIVESDK</filename></link>.
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>FILESDIR</filename>
+                    variable, which was previously deprecated and rarely used,
+                    has now been removed.
+                    You should change any recipes that set
+                    <filename>FILESDIR</filename> to set
+                    <link linkend='var-FILESPATH'><filename>FILESPATH</filename></link>
+                    instead.
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>MULTIMACH_HOST_SYS</filename>
+                    variable has been removed as it is no longer needed
+                    with recipe-specific sysroots.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+</section>
+
+<section id='moving-to-the-yocto-project-2.4-release'>
+    <title>Moving to the Yocto Project 2.4 Release</title>
+
+    <para>
+        This section provides migration information for moving to the
+        Yocto Project 2.4 Release from the prior release.
+    </para>
+
+    <section id='migration-2.4-memory-resident-mode'>
+        <title>Memory Resident Mode</title>
+
+        <para>
+            A persistent mode is now available in BitBake's default operation,
+            replacing its previous "memory resident mode" (i.e.
+            <filename>oe-init-build-env-memres</filename>).
+            Now you only need to set
+            <link linkend='var-BB_SERVER_TIMEOUT'><filename>BB_SERVER_TIMEOUT</filename></link>
+            to a timeout (in seconds) and BitBake's server stays resident for
+            that amount of time between invocations.
+            The <filename>oe-init-build-env-memres</filename> script has been
+            removed since a separate environment setup script is no longer
+            needed.
+        </para>
+    </section>
+
+    <section id='migration-2.4-packaging-changes'>
+        <title>Packaging Changes</title>
+
+        <para>
+            This section provides information about packaging changes that have
+            occurred:
+            <itemizedlist>
+                <listitem><para>
+                    <emphasis><filename>python3</filename> Changes:</emphasis>
+                    <itemizedlist>
+                        <listitem><para>
+                            The main "python3" package now brings in all of the
+                            standard Python 3 distribution rather than a subset.
+                            This behavior matches what is expected based on
+                            traditional Linux distributions.
+                            If you wish to install a subset of Python 3, specify
+                            <filename>python-core</filename> plus one or more of
+                            the individual packages that are still produced.
+                            </para></listitem>
+                        <listitem><para>
+                            <emphasis><filename>python3</filename>:</emphasis>
+                            The <filename>bz2.py</filename>,
+                            <filename>lzma.py</filename>, and
+                            <filename>_compression.py</filename> scripts have
+                            been moved from the
+                            <filename>python3-misc</filename> package to
+                            the <filename>python3-compression</filename> package.
+                            </para></listitem>
+                    </itemizedlist>
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>binutils</filename>:</emphasis>
+                    The <filename>libbfd</filename> library is now packaged in
+                    a separate "libbfd" package.
+                    This packaging saves space when certain tools
+                    (e.g. <filename>perf</filename>) are installed.
+                    In such cases, the tools only need
+                    <filename>libbfd</filename> rather than all the packages in
+                    <filename>binutils</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>util-linux</filename> Changes:</emphasis>
+                    <itemizedlist>
+                        <listitem><para>
+                            The <filename>su</filename> program is now packaged
+                            in a separate "util-linux-su" package, which is only
+                            built when "pam" is listed in the
+                            <link linkend='var-DISTRO_FEATURES'><filename>DISTRO_FEATURES</filename></link>
+                            variable.
+                            <filename>util-linux</filename> should not be
+                            installed unless it is needed because
+                            <filename>su</filename> is normally provided through
+                            the shadow file format.
+                            The main <filename>util-linux</filename> package has
+                            runtime dependencies (i.e.
+                            <link linkend='var-RDEPENDS'><filename>RDEPENDS</filename></link>)
+                            on the <filename>util-linux-su</filename> package
+                            when "pam" is in
+                            <filename>DISTRO_FEATURES</filename>.
+                            </para></listitem>
+                        <listitem><para>
+                            The <filename>switch_root</filename> program is now
+                            packaged in a separate "util-linux-switch-root"
+                            package for small initramfs images that do not need
+                            the whole <filename>util-linux</filename> package or
+                            the busybox binary, which are both much larger than
+                            <filename>switch_root</filename>.
+                            The main <filename>util-linux</filename> package has
+                            a recommended runtime dependency (i.e.
+                            <link linkend='var-RRECOMMENDS'><filename>RRECOMMENDS</filename></link>)
+                            on the <filename>util-linux-switch-root</filename> package.
+                            </para></listitem>
+                        <listitem><para>
+                            The <filename>ionice</filename> program is now
+                            packaged in a separate "util-linux-ionice" package.
+                            The main <filename>util-linux</filename> package has
+                            a recommended runtime dependency (i.e.
+                            <filename>RRECOMMENDS</filename>)
+                            on the <filename>util-linux-ionice</filename> package.
+                            </para></listitem>
+                    </itemizedlist>
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>initscripts</filename>:</emphasis>
+                    The <filename>sushell</filename> program is now packaged in
+                    a separate "initscripts-sushell" package.
+                    This packaging change allows systems to pull
+                    <filename>sushell</filename> in when
+                    <filename>selinux</filename> is enabled.
+                    The change also eliminates needing to pull in the entire
+                    <filename>initscripts</filename> package.
+                    The main <filename>initscripts</filename> package has a
+                    runtime dependency (i.e. <filename>RDEPENDS</filename>)
+                    on the <filename>sushell</filename> package when
+                    "selinux" is in <filename>DISTRO_FEATURES</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>glib-2.0</filename>:</emphasis>
+                    The <filename>glib-2.0</filename> package now has a
+                    recommended runtime dependency (i.e.
+                    <filename>RRECOMMENDS</filename>) on the
+                    <filename>shared-mime-info</filename> package, since large
+                    portions of GIO are not useful without the MIME database.
+                    You can remove the dependency by using the
+                    <link linkend='var-BAD_RECOMMENDATIONS'><filename>BAD_RECOMMENDATIONS</filename></link>
+                    variable if <filename>shared-mime-info</filename> is too
+                    large and is not required.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Go Standard Runtime:</emphasis>
+                    The Go standard runtime has been split out from the main
+                    <filename>go</filename> recipe into a separate
+                    <filename>go-runtime</filename> recipe.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.4-removed-recipes'>
+        <title>Removed Recipes</title>
+
+        <para>
+            The following recipes have been removed:
+            <itemizedlist>
+                <listitem><para>
+                    <emphasis><filename>acpitests</filename>:</emphasis>
+                    This recipe is not maintained.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>autogen-native</filename>:</emphasis>
+                    No longer required by Grub, oe-core, or meta-oe.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>bdwgc</filename>:</emphasis>
+                    Nothing in OpenEmbedded-Core requires this recipe.
+                    It has moved to meta-oe.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>byacc</filename>:</emphasis>
+                    This recipe was only needed by rpm 5.x and has moved to
+                    meta-oe.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>gcc (5.4)</filename>:</emphasis>
+                    The 5.4 series dropped the recipe in favor of 6.3 / 7.2.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>gnome-common</filename>:</emphasis>
+                    Deprecated upstream and no longer needed.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>go-bootstrap-native</filename>:</emphasis>
+                    Go 1.9 does its own bootstrapping so this recipe has been
+                    removed.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>guile</filename>:</emphasis>
+                    This recipe was only needed by
+                    <filename>autogen-native</filename> and
+                    <filename>remake</filename>.
+                    The recipe is no longer needed by either of these programs.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>libclass-isa-perl</filename>:</emphasis>
+                    This recipe was previously needed for LSB 4, no longer
+                    needed.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>libdumpvalue-perl</filename>:</emphasis>
+                    This recipe was previously needed for LSB 4, no longer
+                    needed.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>libenv-perl</filename>:</emphasis>
+                    This recipe was previously needed for LSB 4, no longer
+                    needed.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>libfile-checktree-perl</filename>:</emphasis>
+                    This recipe was previously needed for LSB 4, no longer
+                    needed.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>libi18n-collate-perl</filename>:</emphasis>
+                    This recipe was previously needed for LSB 4, no longer
+                    needed.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>libiconv</filename>:</emphasis>
+                    This recipe was only needed for <filename>uclibc</filename>,
+                    which was removed in the previous release.
+                    <filename>glibc</filename> and <filename>musl</filename>
+                    have their own implementations.
+                    <filename>meta-mingw</filename> still needs
+                    <filename>libiconv</filename>, so it has
+                    been moved to <filename>meta-mingw</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>libpng12</filename>:</emphasis>
+                    This recipe was previously needed for LSB. The current
+                    <filename>libpng</filename> is 1.6.x.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>libpod-plainer-perl</filename>:</emphasis>
+                    This recipe was previously needed for LSB 4, no longer
+                    needed.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>linux-yocto (4.1)</filename>:</emphasis>
+                    This recipe was removed in favor of 4.4, 4.9, 4.10 and 4.12.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>mailx</filename>:</emphasis>
+                    This recipe was previously only needed for LSB
+                    compatibility, and upstream is defunct.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>mesa (git version only)</filename>:</emphasis>
+                    The git version recipe was stale with respect to the release
+                    version.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>ofono (git version only)</filename>:</emphasis>
+                    The git version recipe was stale with respect to the release
+                    version.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>portmap</filename>:</emphasis>
+                    This recipe is obsolete and is superseded by
+                    <filename>rpcbind</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>python3-pygpgme</filename>:</emphasis>
+                    This recipe is old and unmaintained. It was previously
+                    required by <filename>dnf</filename>, which has switched
+                    to official <filename>gpgme</filename> Python bindings.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>python-async</filename>:</emphasis>
+                    This recipe has been removed in favor of the Python 3
+                    version.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>python-gitdb</filename>:</emphasis>
+                    This recipe has been removed in favor of the Python 3
+                    version.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>python-git</filename>:</emphasis>
+                    This recipe was removed in favor of the Python 3
+                    version.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>python-mako</filename>:</emphasis>
+                    This recipe was removed in favor of the Python 3
+                    version.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>python-pexpect</filename>:</emphasis>
+                    This recipe was removed in favor of the Python 3 version.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>python-ptyprocess</filename>:</emphasis>
+                    This recipe was removed in favor of Python the 3 version.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>python-pycurl</filename>:</emphasis>
+                    Nothing is using this recipe in OpenEmbedded-Core
+                    (i.e. <filename>meta-oe</filename>).
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>python-six</filename>:</emphasis>
+                    This recipe was removed in favor of the Python 3 version.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>python-smmap</filename>:</emphasis>
+                    This recipe was removed in favor of the Python 3 version.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>remake</filename>:</emphasis>
+                    Using <filename>remake</filename> as the provider of
+                    <filename>virtual/make</filename> is broken.
+                    Consequently, this recipe is not needed in OpenEmbedded-Core.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.4-kernel-device-tree-move'>
+        <title>Kernel Device Tree Move</title>
+
+        <para>
+            Kernel Device Tree support is now easier to enable in a kernel
+            recipe.
+            The Device Tree code has moved to a
+            <link linkend='ref-classes-kernel-devicetree'><filename>kernel-devicetree</filename></link>
+            class.
+            Functionality is automatically enabled for any recipe that inherits
+            the
+            <link linkend='ref-classes-kernel'><filename>kernel</filename></link>
+            class and sets the
+            <link linkend='var-KERNEL_DEVICETREE'><filename>KERNEL_DEVICETREE</filename></link>
+            variable.
+            The previous mechanism for doing this,
+            <filename>meta/recipes-kernel/linux/linux-dtb.inc</filename>,
+            is still available to avoid breakage, but triggers a
+            deprecation warning.
+            Future releases of the Yocto Project will remove
+            <filename>meta/recipes-kernel/linux/linux-dtb.inc</filename>.
+            It is advisable to remove any <filename>require</filename>
+            statements that request
+            <filename>meta/recipes-kernel/linux/linux-dtb.inc</filename>
+            from any custom kernel recipes you might have.
+            This will avoid breakage in post 2.4 releases.
+        </para>
+    </section>
+
+    <section id='migration-2.4-package-qa-changes'>
+        <title>Package QA Changes</title>
+
+        <para>
+            The following package QA changes took place:
+            <itemizedlist>
+                <listitem><para>
+                    The "unsafe-references-in-scripts" QA check has been
+                    removed.
+                    </para></listitem>
+                <listitem><para>
+                    If you refer to <filename>${COREBASE}/LICENSE</filename>
+                    within
+                    <link linkend='var-LIC_FILES_CHKSUM'><filename>LIC_FILES_CHKSUM</filename></link>
+                    you receive a warning because this file is a description of
+                    the license for OE-Core.
+                    Use <filename>${COMMON_LICENSE_DIR}/MIT</filename>
+                    if your recipe is MIT-licensed and you cannot use the
+                    preferred method of referring to a file within the source
+                    tree.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.4-readme-changes'>
+        <title><filename>README</filename> File Changes</title>
+
+        <para>
+            The following are changes to <filename>README</filename> files:
+            <itemizedlist>
+                <listitem><para>
+                    The main Poky <filename>README</filename> file has been
+                    moved to the <filename>meta-poky</filename> layer and
+                    has been renamed <filename>README.poky</filename>.
+                    A symlink has been created so that references to the old
+                    location work.
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>README.hardware</filename> file has been moved
+                    to <filename>meta-yocto-bsp</filename>.
+                    A symlink has been created so that references to the old
+                    location work.
+                    </para></listitem>
+                <listitem><para>
+                    A <filename>README.qemu</filename> file has been created
+                    with coverage of the <filename>qemu*</filename> machines.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.4-miscellaneous-changes'>
+        <title>Miscellaneous Changes</title>
+
+        <para>
+            The following are additional changes:
+            <itemizedlist>
+                <listitem><para>
+                    The <filename>ROOTFS_PKGMANAGE_BOOTSTRAP</filename>
+                    variable and any references to it have been removed.
+                    You should remove this variable from any custom recipes.
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>meta-yocto</filename> directory has been
+                    removed.
+                    <note>
+                        In the Yocto Project 2.1 release
+                        <filename>meta-yocto</filename> was renamed to
+                        <filename>meta-poky</filename> and the
+                        <filename>meta-yocto</filename> subdirectory remained
+                        to avoid breaking existing configurations.
+                    </note>
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>maintainers.inc</filename> file, which tracks
+                    maintainers by listing a primary person responsible for each
+                    recipe in OE-Core, has been moved from
+                    <filename>meta-poky</filename> to OE-Core (i.e. from
+                    <filename>meta-poky/conf/distro/include</filename> to
+                    <filename>meta/conf/distro/include</filename>).
+                    </para></listitem>
+                <listitem><para>
+                    The
+                    <link linkend='ref-classes-buildhistory'><filename>buildhistory</filename></link>
+                    class now makes a single commit per build rather than one
+                    commit per subdirectory in the repository.
+                    This behavior assumes the commits are enabled with
+                    <link linkend='var-BUILDHISTORY_COMMIT'><filename>BUILDHISTORY_COMMIT</filename></link>
+                    = "1", which is typical.
+                    Previously, the <filename>buildhistory</filename> class made
+                    one commit per subdirectory in the repository in order to
+                    make it easier to see the changes for a particular
+                    subdirectory.
+                    To view a particular change, specify that subdirectory as
+                    the last parameter on the <filename>git show</filename>
+                    or <filename>git diff</filename> commands.
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>x86-base.inc</filename> file, which is
+                    included by all x86-based machine configurations, now sets
+                    <link linkend='var-IMAGE_FSTYPES'><filename>IMAGE_FSTYPES</filename></link>
+                    using <filename>?=</filename> to "live" rather than
+                    appending with <filename>+=</filename>.
+                    This change makes the default easier to override.
+                    </para></listitem>
+                <listitem><para>
+                    BitBake fires multiple "BuildStarted" events when
+                    multiconfig is enabled (one per configuration).
+                    For more information, see the
+                    "<ulink url='&YOCTO_DOCS_BB_URL;#events'>Events</ulink>"
+                    section in the BitBake User Manual.
+                    </para></listitem>
+                <listitem><para>
+                    By default, the <filename>security_flags.inc</filename> file
+                    sets a
+                    <link linkend='var-GCCPIE'><filename>GCCPIE</filename></link>
+                    variable with an option to enable Position Independent
+                    Executables (PIE) within <filename>gcc</filename>.
+                    Enabling PIE in the GNU C Compiler (GCC), makes Return
+                    Oriented Programming (ROP) attacks much more difficult to
+                    execute.
+                    </para></listitem>
+                <listitem><para>
+                    OE-Core now provides a
+                    <filename>bitbake-layers</filename> plugin that implements
+                    a "create-layer" subcommand.
+                    The implementation of this subcommand has resulted in the
+                    <filename>yocto-layer</filename> script being deprecated and
+                    will likely be removed in the next Yocto Project release.
+                    </para></listitem>
+                <listitem><para>
+                      The <filename>vmdk</filename>, <filename>vdi</filename>,
+                      and <filename>qcow2</filename> image file types are now
+                      used in conjunction with the "wic" image type through
+                      <filename>CONVERSION_CMD</filename>.
+                      Consequently, the equivalent image types are now
+                      <filename>wic.vmdk</filename>, <filename>wic.vdi</filename>,
+                      and <filename>wic.qcow2</filename>, respectively.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>do_image_&lt;type&gt;[depends]</filename> has
+                    replaced <filename>IMAGE_DEPENDS_&lt;type&gt;</filename>.
+                    If you have your own classes that implement custom image
+                    types, then you need to update them.
+                    </para></listitem>
+                <listitem><para>
+                    OpenSSL 1.1 has been introduced.
+                    However, the default is still 1.0.x through the
+                    <link linkend='var-PREFERRED_VERSION'><filename>PREFERRED_VERSION</filename></link>
+                    variable.
+                    This preference is set is due to the remaining compatibility
+                    issues with other software.
+                    The
+                    <link linkend='var-PROVIDES'><filename>PROVIDES</filename></link>
+                    variable  in the openssl 1.0 recipe now includes "openssl10"
+                    as a marker that can be used in
+                    <link linkend='var-DEPENDS'><filename>DEPENDS</filename></link>
+                    within recipes that build software that still depend on
+                    OpenSSL 1.0.
+                    </para></listitem>
+                <listitem><para>
+                    To ensure consistent behavior, BitBake's "-r" and "-R"
+                    options (i.e. prefile and postfile), which are used to
+                    read or post-read additional configuration files from the
+                    command line, now only affect the current BitBake command.
+                    Before these BitBake changes, these options would "stick"
+                    for future executions.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+</section>
+
+<section id='moving-to-the-yocto-project-2.5-release'>
+    <title>Moving to the Yocto Project 2.5 Release</title>
+
+    <para>
+        This section provides migration information for moving to the
+        Yocto Project 2.5 Release from the prior release.
+    </para>
+
+    <section id='migration-2.5-packaging-changes'>
+        <title>Packaging Changes</title>
+
+        <para>
+            This section provides information about packaging changes that have
+            occurred:
+            <itemizedlist>
+                <listitem><para>
+                    <emphasis><filename>bind-libs</filename>:</emphasis>
+                    The libraries packaged by the bind recipe are in a
+                    separate <filename>bind-libs</filename> package.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>libfm-gtk</filename>:</emphasis>
+                    The <filename>libfm</filename> GTK+ bindings are split into
+                    a separate <filename>libfm-gtk</filename> package.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>flex-libfl</filename>:</emphasis>
+                    The flex recipe splits out libfl into a separate
+                    <filename>flex-libfl</filename> package to avoid too many
+                    dependencies being pulled in where only the library is
+                    needed.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>grub-efi</filename>:</emphasis>
+                    The <filename>grub-efi</filename> configuration is split
+                    into a separate <filename>grub-bootconf</filename>
+                    recipe.
+                    However, the dependency relationship from
+                    <filename>grub-efi</filename> is through a
+                    virtual/grub-bootconf provider making it possible to have
+                    your own recipe provide the dependency.
+                    Alternatively, you can use a BitBake append file to bring
+                    the configuration back into the
+                    <filename>grub-efi</filename> recipe.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>armv7a Legacy Package Feed Support:</emphasis>
+                    Legacy support is removed for transitioning from
+                    <filename>armv7a</filename> to
+                    <filename>armv7a-vfp-neon</filename> in package feeds,
+                    which was previously enabled by setting
+                    <filename>PKGARCHCOMPAT_ARMV7A</filename>.
+                    This transition occurred in 2011 and active package feeds
+                    should by now be updated to the new naming.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.5-removed-recipes'>
+        <title>Removed Recipes</title>
+
+        <para>
+            The following recipes have been removed:
+            <itemizedlist>
+                <listitem><para>
+                    <emphasis><filename>gcc</filename>:</emphasis>
+                    The version 6.4 recipes are replaced by 7.x.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>gst-player</filename>:</emphasis>
+                    Renamed to <filename>gst-examples</filename> as per
+                    upstream.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>hostap-utils</filename>:</emphasis>
+                    This software package is obsolete.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>latencytop</filename>:</emphasis>
+                    This recipe is no longer maintained upstream.
+                    The last release was in 2009.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>libpfm4</filename>:</emphasis>
+                    The only file that requires this recipe is
+                    <filename>oprofile</filename>, which has been removed.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>linux-yocto</filename>:</emphasis>
+                    The version 4.4, 4.9, and 4.10 recipes have been removed.
+                    Versions 4.12, 4.14, and 4.15 remain.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>man</filename>:</emphasis>
+                    This recipe has been replaced by modern
+                    <filename>man-db</filename>
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>mkelfimage</filename>:</emphasis>
+                    This tool has been removed in the upstream coreboot project,
+                    and is no longer needed with the removal of the ELF image
+                    type.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>nativesdk-postinst-intercept</filename>:</emphasis>
+                    This recipe is not maintained.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>neon</filename>:</emphasis>
+                    This software package is no longer maintained upstream and
+                    is no longer needed by anything in OpenEmbedded-Core.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>oprofile</filename>:</emphasis>
+                    The functionality of this recipe is replaced by
+                    <filename>perf</filename> and keeping compatibility on
+                    an ongoing basis with <filename>musl</filename> is
+                    difficult.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>pax</filename>:</emphasis>
+                    This software package is obsolete.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>stat</filename>:</emphasis>
+                    This software package is not maintained upstream.
+                    <filename>coreutils</filename> provides a modern stat binary.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>zisofs-tools-native</filename>:</emphasis>
+                    This recipe is no longer needed because the compressed
+                    ISO image feature has been removed.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.5-scripts-and-tools-changes'>
+        <title>Scripts and Tools Changes</title>
+
+        <para>
+            The following are changes to scripts and tools:
+            <itemizedlist>
+                <listitem><para>
+                    <emphasis><filename>yocto-bsp</filename>,
+                    <filename>yocto-kernel</filename>, and
+                    <filename>yocto-layer</filename></emphasis>:
+                    The <filename>yocto-bsp</filename>,
+                    <filename>yocto-kernel</filename>, and
+                    <filename>yocto-layer</filename> scripts previously shipped
+                    with poky but not in OpenEmbedded-Core have been removed.
+                    These scripts are not maintained and are outdated.
+                    In many cases, they are also limited in scope.
+                    The <filename>bitbake-layers create-layer</filename> command
+                    is a direct replacement for <filename>yocto-layer</filename>.
+                    See the documentation to create a BSP or kernel recipe in
+                    the
+                    "<ulink url='&YOCTO_DOCS_BSP_URL;#bsp-kernel-recipe-example'>BSP Kernel Recipe Example</ulink>"
+                     section.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>devtool finish</filename>:</emphasis>
+                    <filename>devtool finish</filename> now exits with an error
+                    if there are uncommitted changes or a rebase/am in progress
+                    in the recipe's source repository.
+                    If this error occurs, there might be uncommitted changes
+                    that will not be included in updates to the patches applied
+                    by the recipe.
+                    A -f/--force option is provided for situations that the
+                    uncommitted changes are inconsequential and you want to
+                    proceed regardless.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>scripts/oe-setup-rpmrepo</filename> script:</emphasis>
+                    The functionality of
+                    <filename>scripts/oe-setup-rpmrepo</filename> is replaced by
+                    <filename>bitbake package-index</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>scripts/test-dependencies.sh</filename> script:</emphasis>
+                    The script is largely made obsolete by the
+                    recipe-specific sysroots functionality introduced in the
+                    previous release.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.5-bitbake-changes'>
+        <title>BitBake Changes</title>
+
+        <para>
+            The following are BitBake changes:
+            <itemizedlist>
+                <listitem><para>
+                    The <filename>--runall</filename> option has changed.
+                    There are two different behaviors people might want:
+                    <itemizedlist>
+                        <listitem><para>
+                            <emphasis>Behavior A:</emphasis>
+                            For a given target (or set of targets) look through
+                            the task graph and run task X only if it is present
+                            and will be built.
+                            </para></listitem>
+                        <listitem><para>
+                            <emphasis>Behavior B:</emphasis>
+                            For a given target (or set of targets) look through
+                            the task graph and run task X if any recipe in the
+                            taskgraph has such a target, even if it is not in
+                            the original task graph.
+                            </para></listitem>
+                    </itemizedlist>
+                    The <filename>--runall</filename> option now performs
+                    "Behavior B".
+                    Previously <filename>--runall</filename> behaved like
+                    "Behavior A".
+                    A <filename>--runonly</filename> option has been added to
+                    retain the ability to perform "Behavior A".
+                    </para></listitem>
+                <listitem><para>
+                    Several explicit "run this task for all recipes in the
+                    dependency tree" tasks have been removed (e.g.
+                    <filename>fetchall</filename>,
+                    <filename>checkuriall</filename>, and the
+                    <filename>*all</filename> tasks provided by the
+                    <filename>distrodata</filename> and
+                    <filename>archiver</filename> classes).
+                    There is a BitBake option to complete this for any arbitrary
+                    task. For example:
+                    <literallayout class='monospaced'>
+     bitbake &lt;target&gt; -c fetchall
+                    </literallayout>
+                    should now be replaced with:
+                    <literallayout class='monospaced'>
+     bitbake &lt;target&gt; --runall=fetch
+                    </literallayout>
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.5-python-and-python3-changes'>
+        <title>Python and Python 3 Changes</title>
+
+        <para>
+            The following are auto-packaging changes to Python and Python 3:
+        </para>
+        <para>
+            The script-managed <filename>python-*-manifest.inc</filename> files
+            that were previously used to generate Python and Python 3
+            packages have been replaced with a JSON-based file that is
+            easier to read and maintain.
+            A new task is available for maintainers of the Python recipes to
+            update the JSON file when upgrading to new Python versions.
+            You can now edit the file directly instead of having to edit a
+            script and run it to update the file.
+        </para>
+        <para>
+            One particular change to note is that the Python recipes no longer
+            have build-time provides for their packages.
+            This assumes <filename>python-foo</filename> is one of the packages
+            provided by the Python recipe.
+            You can no longer run <filename>bitbake python-foo</filename> or
+            have a <ulink url='&YOCTO_DOCS_REF_URL;#var-DEPENDS'><filename>DEPENDS</filename></ulink> on
+            <filename>python-foo</filename>, but doing either of the following
+            causes the package to work as expected:
+            <literallayout class='monospaced'>
+     IMAGE_INSTALL_append = " python-foo"
+            </literallayout>
+            or
+            <literallayout class='monospaced'>
+     RDEPENDS_${PN} = "python-foo"
+            </literallayout>
+            The earlier build-time provides behavior was a quirk of the way the
+            Python manifest file was created.
+            For more information on this change please see
+            <ulink url='http://git.yoctoproject.org/cgit/cgit.cgi/poky/commit/?id=8d94b9db221d1def42f091b991903faa2d1651ce'>this commit</ulink>.
+        </para>
+    </section>
+
+    <section id='migration-2.5-miscellaneous-changes'>
+        <title>Miscellaneous Changes</title>
+
+        <para>
+            The following are additional changes:
+            <itemizedlist>
+                <listitem><para>
+                    The <filename>kernel</filename> class supports building
+                    packages for multiple kernels.
+                    If your kernel recipe or <filename>.bbappend</filename> file
+                    mentions packaging at all, you should replace references to
+                    the kernel in package names with
+                    <filename>${KERNEL_PACKAGE_NAME}</filename>.
+                    For example, if you disable automatic installation of the
+                    kernel image using
+                    <filename>RDEPENDS_kernel-base = ""</filename> you can avoid
+                    warnings using
+                    <filename>RDEPENDS_${KERNEL_PACKAGE_NAME}-base = ""</filename>
+                    instead.
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>buildhistory</filename> class commits changes
+                    to the repository by default so you no longer need to set
+                    <filename>BUILDHISTORY_COMMIT = "1"</filename>.
+                    If you want to disable commits you need to set
+                    <filename>BUILDHISTORY_COMMIT = "0"</filename> in your
+                    configuration.
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>beaglebone</filename> reference machine has
+                    been renamed to <filename>beaglebone-yocto</filename>.
+                    The <filename>beaglebone-yocto</filename> BSP is a reference
+                    implementation using only mainline components available in
+                    OpenEmbedded-Core and <filename>meta-yocto-bsp</filename>,
+                    whereas Texas Instruments maintains a full-featured BSP in
+                    the <filename>meta-ti</filename> layer.
+                    This rename avoids the previous name clash that existed
+                    between the two BSPs.
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>update-alternatives</filename> class no longer
+                    works with SysV <filename>init</filename> scripts because
+                    this usage has been problematic.
+                    Also, the <filename>sysklogd</filename> recipe no longer
+                    uses <filename>update-alternatives</filename> because it is
+                    incompatible with other implementations.
+                    </para></listitem>
+                <listitem><para>
+                    By default, the
+                    <link linkend='ref-classes-cmake'><filename>cmake</filename></link>
+                    class uses <filename>ninja</filename> instead of
+                    <filename>make</filename> for building.
+                    This improves build performance.
+                    If a recipe is broken with <filename>ninja</filename>, then
+                    the recipe can set
+                    <filename>OECMAKE_GENERATOR = "Unix Makefiles"</filename>
+                    to change back to <filename>make</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    The previously deprecated <filename>base_*</filename>
+                    functions have been removed in favor of their replacements
+                    in <filename>meta/lib/oe</filename> and
+                    <filename>bitbake/lib/bb</filename>.
+                    These are typically used from recipes and classes.
+                    Any references to the old functions must be updated.
+                    The following table shows the removed functions and their
+                    replacements:
+
+                    <literallayout class='monospaced'>
+     <emphasis>Removed</emphasis>                                 <emphasis>Replacement</emphasis>
+     ============================            ============================
+     base_path_join()                        oe.path.join()
+     base_path_relative()                    oe.path.relative()
+     base_path_out()                         oe.path.format_display()
+     base_read_file()                        oe.utils.read_file()
+     base_ifelse()                           oe.utils.ifelse()
+     base_conditional()                      oe.utils.conditional()
+     base_less_or_equal()                    oe.utils.less_or_equal()
+     base_version_less_or_equal()            oe.utils.version_less_or_equal()
+     base_contains()                         bb.utils.contains()
+     base_both_contain()                     oe.utils.both_contain()
+     base_prune_suffix()                     oe.utils.prune_suffix()
+     oe_filter()                             oe.utils.str_filter()
+     oe_filter_out()                         oe.utils.str_filter_out() (or use the _remove operator).
+                    </literallayout>
+                    </para></listitem>
+                <listitem><para>
+                    Using <filename>exit 1</filename> to explicitly defer a
+                    postinstall script until first boot is now deprecated since
+                    it is not an obvious mechanism and can mask actual errors.
+                    If you want to explicitly defer a postinstall to first boot
+                    on the target rather than at <filename>rootfs</filename>
+                    creation time, use
+                    <filename>pkg_postinst_ontarget()</filename>
+                    or call
+                    <filename>postinst_intercept delay_to_first_boot</filename>
+                    from <filename>pkg_postinst()</filename>.
+                    Any failure of a <filename>pkg_postinst()</filename>
+                    script (including <filename>exit 1</filename>)
+                    will trigger a warning during
+                    <filename>do_rootfs</filename>.</para>
+
+                    <para>For more information, see the
+                    "<ulink url='&YOCTO_DOCS_DEV_URL;#new-recipe-post-installation-scripts'>Post-Installation Scripts</ulink>"
+                    section in the Yocto Project Development Tasks Manual.
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>elf</filename> image type has been removed.
+                    This image type was removed because the
+                    <filename>mkelfimage</filename> tool
+                    that was required to create it is no longer provided by
+                    coreboot upstream and required updating every time
+                    <filename>binutils</filename> updated.
+                    </para></listitem>
+                <listitem><para>
+                    Support for .iso image compression (previously enabled
+                    through <filename>COMPRESSISO = "1"</filename>) has been
+                    removed.
+                    The userspace tools (<filename>zisofs-tools</filename>) are
+                    unmaintained and <filename>squashfs</filename> provides
+                    better performance and compression.
+                    In order to build a live image with squashfs+lz4 compression
+                    enabled you should now set
+                    <filename>LIVE_ROOTFS_TYPE = "squashfs-lz4"</filename>
+                    and ensure that <filename>live</filename>
+                    is in <filename>IMAGE_FSTYPES</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    Recipes with an unconditional dependency on
+                    <filename>libpam</filename> are only buildable with
+                    <filename>pam</filename> in
+                    <filename>DISTRO_FEATURES</filename>.
+                    If the dependency is truly optional then it is recommended
+                    that the dependency be conditional upon
+                    <filename>pam</filename> being in
+                    <filename>DISTRO_FEATURES</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    For EFI-based machines, the bootloader
+                    (<filename>grub-efi</filename> by default) is installed into
+                    the image at /boot.
+                    Wic can be used to split the bootloader into separate boot
+                    and rootfs partitions if necessary.
+                    </para></listitem>
+                <listitem><para>
+                    Patches whose context does not match exactly (i.e. where
+                    patch reports "fuzz" when applying) will generate a
+                    warning.
+                    For an example of this see
+                    <ulink url='http://git.yoctoproject.org/cgit/cgit.cgi/poky/commit/?id=cc97bc08125b63821ce3f616771830f77c456f57'>this commit</ulink>.
+                    </para></listitem>
+                <listitem><para>
+                    Layers are expected to set
+                    <filename>LAYERSERIES_COMPAT_layername</filename>
+                    to match the version(s) of OpenEmbedded-Core they are
+                    compatible with.
+                    This is specified as codenames using spaces to separate
+                    multiple values (e.g. "rocko sumo").
+                    If a layer does not set
+                    <filename>LAYERSERIES_COMPAT_layername</filename>, a warning
+                    will is shown.
+                    If a layer sets a value that does not include the current
+                    version ("sumo" for the 2.5 release), then an error will be
+                    produced.
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>TZ</filename> environment variable is set to
+                    "UTC" within the build environment in order to fix
+                    reproducibility problems in some recipes.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+</section>
+
+<section id='moving-to-the-yocto-project-2.6-release'>
+    <title>Moving to the Yocto Project 2.6 Release</title>
+
+    <para>
+        This section provides migration information for moving to the
+        Yocto Project 2.6 Release from the prior release.
+    </para>
+
+    <section id='migration-2.6-gcc-changes'>
+        <title>GCC 8.2 is Now Used by Default</title>
+
+        <para>
+            The GNU Compiler Collection version 8.2 is now used by default
+            for compilation.
+            For more information on what has changed in the GCC 8.x release,
+            see
+            <ulink url='https://gcc.gnu.org/gcc-8/changes.html'></ulink>.
+        </para>
+
+        <para>
+            If you still need to compile with version 7.x, GCC 7.3 is
+            also provided.
+            You can select this version by setting the
+            and can be selected by setting the
+            <link linkend='var-GCCVERSION'><filename>GCCVERSION</filename></link>
+            variable to "7.%" in your configuration.
+        </para>
+    </section>
+
+    <section id='migration-2.6-removed-recipes'>
+        <title>Removed Recipes</title>
+
+        <para>
+            The following recipes have been removed:
+            <literallayout class='monospaced'>
+     <emphasis><filename>beecrypt</filename>:</emphasis> No longer needed since moving to RPM 4.
+     <emphasis><filename>bigreqsproto</filename>:</emphasis> Replaced by <filename>xorgproto</filename>.
+     <emphasis><filename>calibrateproto</filename>:</emphasis> Removed in favor of <filename>xinput</filename>.
+     <emphasis><filename>compositeproto</filename>:</emphasis> Replaced by <filename>xorgproto</filename>.
+     <emphasis><filename>damageproto</filename>:</emphasis> Replaced by <filename>xorgproto</filename>.
+     <emphasis><filename>dmxproto</filename>:</emphasis> Replaced by <filename>xorgproto</filename>.
+     <emphasis><filename>dri2proto</filename>:</emphasis> Replaced by <filename>xorgproto</filename>.
+     <emphasis><filename>dri3proto</filename>:</emphasis> Replaced by <filename>xorgproto</filename>.
+     <emphasis><filename>eee-acpi-scripts</filename>:</emphasis> Became obsolete.
+     <emphasis><filename>fixesproto</filename>:</emphasis> Replaced by <filename>xorgproto</filename>.
+     <emphasis><filename>fontsproto</filename>:</emphasis> Replaced by <filename>xorgproto</filename>.
+     <emphasis><filename>fstests</filename>:</emphasis> Became obsolete.
+     <emphasis><filename>gccmakedep</filename>:</emphasis> No longer used.
+     <emphasis><filename>glproto</filename>:</emphasis> Replaced by <filename>xorgproto</filename>.
+     <emphasis><filename>gnome-desktop3</filename>:</emphasis> No longer needed.  This recipe has moved to <filename>meta-oe</filename>.
+     <emphasis><filename>icon-naming-utils</filename>:</emphasis> No longer used since the Sato theme was removed in 2016.
+     <emphasis><filename>inputproto</filename>:</emphasis> Replaced by <filename>xorgproto</filename>.
+     <emphasis><filename>kbproto</filename>:</emphasis> Replaced by <filename>xorgproto</filename>.
+     <emphasis><filename>libusb-compat</filename>:</emphasis> Became obsolete.
+     <emphasis><filename>libuser</filename>:</emphasis> Became obsolete.
+     <emphasis><filename>libnfsidmap</filename>:</emphasis> No longer an external requirement since <filename>nfs-utils</filename> 2.2.1.  <filename>libnfsidmap</filename> is now integrated.
+     <emphasis><filename>libxcalibrate</filename>:</emphasis> No longer needed with <filename>xinput</filename>
+     <emphasis><filename>mktemp</filename>:</emphasis> Became obsolete. The <filename>mktemp</filename> command is provided by both <filename>busybox</filename> and <filename>coreutils</filename>.
+     <emphasis><filename>ossp-uuid</filename>:</emphasis> Is not being maintained and has mostly been replaced by <filename>uuid.h</filename> in <filename>util-linux</filename>.
+     <emphasis><filename>pax-utils</filename>:</emphasis> No longer needed.  Previous QA tests that did use this recipe are now done at build time.
+     <emphasis><filename>pcmciautils</filename>:</emphasis> Became obsolete.
+     <emphasis><filename>pixz</filename>:</emphasis> No longer needed. <filename>xz</filename> now supports multi-threaded compression.
+     <emphasis><filename>presentproto</filename>:</emphasis> Replaced by <filename>xorgproto</filename>.
+     <emphasis><filename>randrproto</filename>:</emphasis> Replaced by <filename>xorgproto</filename>.
+     <emphasis><filename>recordproto</filename>:</emphasis> Replaced by <filename>xorgproto</filename>.
+     <emphasis><filename>renderproto</filename>:</emphasis> Replaced by <filename>xorgproto</filename>.
+     <emphasis><filename>resourceproto</filename>:</emphasis> Replaced by <filename>xorgproto</filename>.
+     <emphasis><filename>scrnsaverproto</filename>:</emphasis> Replaced by <filename>xorgproto</filename>.
+     <emphasis><filename>trace-cmd</filename>:</emphasis> Became obsolete.  <filename>perf</filename> replaced this recipe's functionally.
+     <emphasis><filename>videoproto</filename>:</emphasis> Replaced by <filename>xorgproto</filename>.
+     <emphasis><filename>wireless-tools</filename>:</emphasis> Became obsolete.  Superseded by <filename>iw</filename>.
+     <emphasis><filename>xcmiscproto</filename>:</emphasis> Replaced by <filename>xorgproto</filename>.
+     <emphasis><filename>xextproto</filename>:</emphasis> Replaced by <filename>xorgproto</filename>.
+     <emphasis><filename>xf86dgaproto</filename>:</emphasis> Replaced by <filename>xorgproto</filename>.
+     <emphasis><filename>xf86driproto</filename>:</emphasis> Replaced by <filename>xorgproto</filename>.
+     <emphasis><filename>xf86miscproto</filename>:</emphasis> Replaced by <filename>xorgproto</filename>.
+     <emphasis><filename>xf86-video-omapfb</filename>:</emphasis> Became obsolete.  Use kernel modesetting driver instead.
+     <emphasis><filename>xf86-video-omap</filename>:</emphasis> Became obsolete.  Use kernel modesetting driver instead.
+     <emphasis><filename>xf86vidmodeproto</filename>:</emphasis> Replaced by <filename>xorgproto</filename>.
+     <emphasis><filename>xineramaproto</filename>:</emphasis> Replaced by <filename>xorgproto</filename>.
+     <emphasis><filename>xproto</filename>:</emphasis> Replaced by <filename>xorgproto</filename>.
+     <emphasis><filename>yasm</filename>:</emphasis> No longer needed since previous usages are now satisfied by <filename>nasm</filename>.
+            </literallayout>
+        </para>
+    </section>
+
+    <section id='migration-2.6-packaging-changes'>
+        <title>Packaging Changes</title>
+
+        <para>
+            The following packaging changes have been made:
+            <itemizedlist>
+                <listitem><para>
+                    <emphasis><filename>cmake</filename>:</emphasis>
+                    <filename>cmake.m4</filename> and
+                    <filename>toolchain</filename> files have been moved to the
+                    main package.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>iptables</filename>:</emphasis>
+                    The <filename>iptables</filename> modules have been split
+                    into separate packages.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>alsa-lib</filename>:</emphasis>
+                    <filename>libasound</filename> is now in the main
+                    <filename>alsa-lib</filename> package instead of
+                    <filename>libasound</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>glibc</filename>:</emphasis>
+                    <filename>libnss-db</filename> is now in its own package
+                    along with a <filename>/var/db/makedbs.sh</filename>
+                    script to update databases.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>python</filename> and <filename>python3</filename>:</emphasis>
+                    The main package has been removed from the recipe.
+                    You must install specific packages or
+                    <filename>python-modules</filename> /
+                    <filename>python3-modules</filename> for everything.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis><filename>systemtap</filename>:</emphasis>
+                    Moved <filename>systemtap-exporter</filename> into its own
+                    package.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.6-xorg-protocol-dependencies'>
+        <title>XOrg Protocol dependencies</title>
+
+        <para>
+            The "*proto" upstream repositories have been combined into one
+            "xorgproto" repository.
+            Thus, the corresponding recipes have also been combined into a
+            single <filename>xorgproto</filename> recipe.
+            Any recipes that depend upon the older <filename>*proto</filename>
+            recipes need to be changed to depend on the newer
+            <filename>xorgproto</filename> recipe instead.
+        </para>
+
+        <para>
+            For names of recipes removed because of this repository change,
+            see the
+            <link linkend="migration-2.6-removed-recipes">Removed Recipes</link>
+            section.
+        </para>
+    </section>
+
+    <section id='migration-2.6-distutils-distutils3-fetching-dependencies'>
+        <title><filename>distutils</filename> and <filename>distutils3</filename> Now Prevent Fetching Dependencies During the <filename>do_configure</filename> Task</title>
+
+        <para>
+            Previously, it was possible for Python recipes that inherited
+            the
+            <link linkend='ref-classes-distutils'><filename>distutils</filename></link>
+            and
+            <link linkend='ref-classes-distutils3'><filename>distutils3</filename></link>
+            classes to fetch code during the
+            <link linkend='ref-tasks-configure'><filename>do_configure</filename></link>
+            task to satisfy dependencies mentioned in
+            <filename>setup.py</filename> if those dependencies were not
+            provided in the sysroot (i.e. recipes providing the dependencies
+            were missing from
+            <link linkend='var-DEPENDS'><filename>DEPENDS</filename></link>).
+            <note>
+                This change affects classes beyond just the two mentioned
+                (i.e. <filename>distutils</filename> and
+                <filename>distutils3</filename>).
+                Any recipe that inherits <filename>distutils*</filename>
+                classes are affected.
+                For example, the <filename>setuptools</filename> and
+                <filename>setuptools3</filename> recipes are affected since
+                they inherit the <filename>distutils*</filename> classes.
+            </note>
+        </para>
+
+        <para>
+            Fetching these types of dependencies that are not provided in the
+            sysroot negatively affects the ability to reproduce builds.
+            This type of fetching is now explicitly disabled.
+            Consequently, any missing dependencies in Python recipes that
+            use these classes now result in an error during the
+            <filename>do_configure</filename> task.
+        </para>
+    </section>
+
+    <section id='migration-2.6-linux-yocto-configuration-audit-issues-now-correctly-reported'>
+        <title><filename>linux-yocto</filename> Configuration Audit Issues Now Correctly Reported</title>
+
+        <para>
+            Due to a bug, the kernel configuration audit functionality was
+            not writing out any resulting warnings during the build.
+            This issue is now corrected.
+            You might notice these warnings now if you have a custom kernel
+            configuration with a <filename>linux-yocto</filename> style
+            kernel recipe.
+        </para>
+    </section>
+
+    <section id='migration-2.6-image-kernel-artifact-naming-changes'>
+        <title>Image/Kernel Artifact Naming Changes</title>
+
+        <para>
+            The following changes have been made:
+            <itemizedlist>
+                <listitem><para>
+                    Name variables (e.g.
+                    <link linkend='var-IMAGE_NAME'><filename>IMAGE_NAME</filename></link>)
+                    use a new <filename>IMAGE_VERSION_SUFFIX</filename>
+                    variable instead of
+                    <link linkend='var-DATETIME'><filename>DATETIME</filename></link>.
+                    Using <filename>IMAGE_VERSION_SUFFIX</filename> allows
+                    easier and more direct changes.</para>
+
+                    <para>The <filename>IMAGE_VERSION_SUFFIX</filename>
+                    variable is set in the
+                    <filename>bitbake.conf</filename> configuration file as
+                    follows:
+                    <literallayout class='monospaced'>
+     IMAGE_VERSION_SUFFIX = "-${DATETIME}"
+                    </literallayout>
+                    </para></listitem>
+                <listitem><para>
+                    Several variables have changed names for consistency:
+                    <literallayout class='monospaced'>
+    Old Variable Name               New Variable Name
+    ========================================================
+    KERNEL_IMAGE_BASE_NAME          <link linkend='var-KERNEL_IMAGE_NAME'>KERNEL_IMAGE_NAME</link>
+    KERNEL_IMAGE_SYMLINK_NAME       <link linkend='var-KERNEL_IMAGE_LINK_NAME'>KERNEL_IMAGE_LINK_NAME</link>
+    MODULE_TARBALL_BASE_NAME        <link linkend='var-MODULE_TARBALL_NAME'>MODULE_TARBALL_NAME</link>
+    MODULE_TARBALL_SYMLINK_NAME     <link linkend='var-MODULE_TARBALL_LINK_NAME'>MODULE_TARBALL_LINK_NAME</link>
+    INITRAMFS_BASE_NAME             <link linkend='var-INITRAMFS_NAME'>INITRAMFS_NAME</link>
+                    </literallayout>
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>MODULE_IMAGE_BASE_NAME</filename> variable
+                    has been removed.
+                    The module tarball name is now controlled directly with the
+                    <link linkend='var-MODULE_TARBALL_NAME'><filename>MODULE_TARBALL_NAME</filename></link>
+                    variable.
+                    </para></listitem>
+                <listitem><para>
+                    The
+                    <link linkend='var-KERNEL_DTB_NAME'><filename>KERNEL_DTB_NAME</filename></link>
+                    and
+                    <link linkend='var-KERNEL_DTB_LINK_NAME'><filename>KERNEL_DTB_LINK_NAME</filename></link>
+                    variables have been introduced to control kernel Device
+                    Tree Binary (DTB) artifact names instead of mangling
+                    <filename>KERNEL_IMAGE_*</filename> variables.
+                    </para></listitem>
+                <listitem><para>
+                    The
+                    <link linkend='var-KERNEL_FIT_NAME'><filename>KERNEL_FIT_NAME</filename></link>
+                    and
+                    <link linkend='var-KERNEL_FIT_LINK_NAME'><filename>KERNEL_FIT_LINK_NAME</filename></link>
+                    variables have been introduced to specify the name of
+                    flattened image tree (FIT) kernel images similar to other
+                    deployed artifacts.
+                    </para></listitem>
+                <listitem><para>
+                    The
+                    <link linkend='var-MODULE_TARBALL_NAME'><filename>MODULE_TARBALL_NAME</filename></link>
+                    and
+                    <link linkend='var-MODULE_TARBALL_LINK_NAME'><filename>MODULE_TARBALL_LINK_NAME</filename></link>
+                    variable values no longer include the "module-" prefix or
+                    ".tgz" suffix.
+                    These parts are now hardcoded so that the values are
+                    consistent with other artifact naming variables.
+                    </para></listitem>
+                <listitem><para>
+                    Added the
+                    <link linkend='var-INITRAMFS_LINK_NAME'><filename>INITRAMFS_LINK_NAME</filename></link>
+                    variable so that the symlink can be controlled similarly
+                    to other artifact types.
+                    </para></listitem>
+                <listitem><para>
+                    <link linkend='var-INITRAMFS_NAME'><filename>INITRAMFS_NAME</filename></link>
+                    now uses
+                    "${PKGE}-${PKGV}-${PKGR}-${MACHINE}${IMAGE_VERSION_SUFFIX}"
+                    instead of
+                    "${PV}-${PR}-${MACHINE}-${DATETIME}", which
+                    makes it consistent with other variables.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.6-serial-console-deprecated'>
+        <title><filename>SERIAL_CONSOLE</filename> Deprecated</title>
+
+        <para>
+            The
+            <link linkend='var-SERIAL_CONSOLE'><filename>SERIAL_CONSOLE</filename></link>
+            variable has been functionally replaced by the
+            <link linkend='var-SERIAL_CONSOLES'><filename>SERIAL_CONSOLES</filename></link>
+            variable for some time.
+            With the Yocto Project 2.6 release,
+            <filename>SERIAL_CONSOLE</filename> has been officially deprecated.
+        </para>
+
+        <para>
+            <filename>SERIAL_CONSOLE</filename> will continue to work as
+            before for the 2.6 release.
+            However, for the sake of future compatibility, it is recommended
+            that you replace all instances of
+            <filename>SERIAL_CONSOLE</filename> with
+            <filename>SERIAL_CONSOLES</filename>.
+            <note>
+                The only difference in usage is that
+                <filename>SERIAL_CONSOLES</filename> expects entries to be
+                separated using semicolons as compared to
+                <filename>SERIAL_CONSOLE</filename>, which expects spaces.
+            </note>
+        </para>
+    </section>
+
+    <section id='migration-2.6-poky-sets-unknown-configure-option-to-qa-error'>
+        <title>Configure Script Reports Unknown Options as Errors</title>
+
+        <para>
+            If the configure script reports an unknown option, this now
+            triggers a QA error instead of a warning.
+            Any recipes that previously got away with specifying such unknown
+            options now need to be fixed.
+        </para>
+    </section>
+
+    <section id='migration-2.6-override-changes'>
+        <title>Override Changes</title>
+
+        <para>
+            The following changes have occurred:
+            <itemizedlist>
+                <listitem><para>
+                    <emphasis>The <filename>virtclass-native</filename> and
+                    <filename>virtclass-nativesdk</filename> Overrides Have
+                    Been Removed:</emphasis>
+                    The <filename>virtclass-native</filename> and
+                    <filename>virtclass-nativesdk</filename> overrides have
+                    been deprecated since 2012 in favor of
+                    <filename>class-native</filename> and
+                    <filename>class-nativesdk</filename>, respectively.
+                    Both <filename>virtclass-native</filename> and
+                    <filename>virtclass-nativesdk</filename> are now dropped.
+                    <note>
+                        The <filename>virtclass-multilib-</filename> overrides
+                        for multilib are still valid.
+                    </note>
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>The <filename>forcevariable</filename>
+                    Override Now Has a Higher Priority Than
+                    <filename>libc</filename> Overrides:</emphasis>
+                    The <filename>forcevariable</filename> override is
+                    documented to be the highest priority override.
+                    However, due to a long-standing quirk of how
+                    <link linkend='var-OVERRIDES'><filename>OVERRIDES</filename></link>
+                    is set, the <filename>libc</filename> overrides (e.g.
+                    <filename>libc-glibc</filename>,
+                    <filename>libc-musl</filename>, and so forth) erroneously
+                    had a higher priority.
+                    This issue is now corrected.</para>
+
+                    <para>It is likely this change will not cause any
+                    problems.
+                    However, it is possible with some unusual configurations
+                    that you might see a change in behavior if you were
+                    relying on the previous behavior.
+                    Be sure to check how you use
+                    <filename>forcevariable</filename> and
+                    <filename>libc-*</filename> overrides in your custom
+                    layers and configuration files to ensure they make sense.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>The <filename>build-${BUILD_OS}</filename>
+                    Override Has Been Removed:</emphasis>
+                    The <filename>build-${BUILD_OS}</filename>, which is
+                    typically <filename>build-linux</filename>, override has
+                    been removed because building on a host operating system
+                    other than a recent version of Linux is neither supported
+                    nor recommended.
+                    Dropping the override avoids giving the impression that
+                    other host operating systems might be supported.
+                    </para></listitem>
+                <listitem><para>
+                    The "_remove" operator now preserves whitespace.
+                    Consequently, when specifying list items to remove, be
+                    aware that leading and trailing whitespace resulting from
+                    the removal is retained.</para>
+
+                    <para>See the
+                    "<ulink url='&YOCTO_DOCS_BB_URL;#removing-override-style-syntax'>Removal (Override Style Syntax)</ulink>"
+                    section in the BitBake User Manual for a detailed example.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.6-systemd-configuration-now-split-out-to-system-conf'>
+        <title><filename>systemd</filename> Configuration is Now Split Into <filename>systemd-conf</filename></title>
+
+        <para>
+            The configuration for the <filename>systemd</filename> recipe
+            has been moved into a <filename>system-conf</filename> recipe.
+            Moving this configuration to a separate recipe avoids the
+            <filename>systemd</filename> recipe from becoming machine-specific
+            for cases where machine-specific configurations need to be applied
+            (e.g. for <filename>qemu*</filename> machines).
+        </para>
+
+        <para>
+            Currently, the new recipe packages the following files:
+            <literallayout class='monospaced'>
+     ${sysconfdir}/machine-id
+     ${sysconfdir}/systemd/coredump.conf
+     ${sysconfdir}/systemd/journald.conf
+     ${sysconfdir}/systemd/logind.conf
+     ${sysconfdir}/systemd/system.conf
+     ${sysconfdir}/systemd/user.conf
+            </literallayout>
+            If you previously used bbappend files to append the
+            <filename>systemd</filename> recipe to change any of the
+            listed files, you must do so for the
+            <filename>systemd-conf</filename> recipe instead.
+        </para>
+    </section>
+
+    <section id='migration-2.6-automatic-testing-changes'>
+        <title>Automatic Testing Changes</title>
+
+        <para>
+            This section provides information about automatic testing
+            changes:
+            <itemizedlist>
+                <listitem><para>
+                    <emphasis><filename>TEST_IMAGE</filename> Variable Removed:</emphasis>
+                    Prior to this release, you set the
+                    <filename>TEST_IMAGE</filename> variable to "1" to
+                    enable automatic testing for successfully built images.
+                    The <filename>TEST_IMAGE</filename> variable no longer
+                    exists and has been replaced by the
+                    <link linkend='var-TESTIMAGE_AUTO'><filename>TESTIMAGE_AUTO</filename></link>
+                    variable.
+                    </para></listitem>
+                <listitem><para>
+                    <emphasis>Inheriting the <filename>testimage</filename> and
+                    <filename>testsdk</filename> Classes:</emphasis>
+                    Best practices now dictate that you use the
+                    <link linkend='var-IMAGE_CLASSES'><filename>IMAGE_CLASSES</filename></link>
+                    variable rather than the
+                    <link linkend='var-INHERIT'><filename>INHERIT</filename></link>
+                    variable when you inherit the
+                    <link linkend='ref-classes-testimage*'><filename>testimage</filename></link>
+                    and
+                    <link linkend='ref-classes-testsdk'><filename>testsdk</filename></link>
+                    classes used for automatic testing.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.6-openssl-changes'>
+        <title>OpenSSL Changes</title>
+
+        <para>
+            <ulink url='https://www.openssl.org/'>OpenSSL</ulink> has been
+            upgraded from 1.0 to 1.1.
+            By default, this upgrade could cause problems for recipes that
+            have both versions in their dependency chains.
+            The problem is that both versions cannot be installed together
+            at build time.
+            <note>
+                It is possible to have both versions of the library at runtime.
+            </note>
+        </para>
+    </section>
+
+    <section id='migration-2.6-bitbake-changes'>
+        <title>BitBake Changes</title>
+
+        <para>
+            The server logfile <filename>bitbake-cookerdaemon.log</filename> is
+            now always placed in the
+            <link linkend='build-directory'>Build Directory</link>
+            instead of the current directory.
+        </para>
+    </section>
+
+    <section id='migration-2.6-security-changes'>
+        <title>Security Changes</title>
+
+        <para>
+            The Poky distribution now uses security compiler flags by
+            default.
+            Inclusion of these flags could cause new failures due to stricter
+            checking for various potential security issues in code.
+        </para>
+    </section>
+
+    <section id='migration-2.6-post-installation-changes'>
+        <title>Post Installation Changes</title>
+
+        <para>
+            You must explicitly mark post installs to defer to the target.
+            If you want to explicitly defer a postinstall to first boot on
+            the target rather than at rootfs creation time, use
+            <filename>pkg_postinst_ontarget()</filename> or call
+            <filename>postinst_intercept delay_to_first_boot</filename> from
+            <filename>pkg_postinst()</filename>.
+            Any failure of a <filename>pkg_postinst()</filename> script
+            (including exit 1) triggers an error during the
+            <link linkend='ref-tasks-rootfs'><filename>do_rootfs</filename></link> task.
+        </para>
+
+        <para>
+            For more information on post-installation behavior, see the
+            "<ulink url='&YOCTO_DOCS_DEV_URL;#new-recipe-post-installation-scripts'>Post-Installation Scripts</ulink>"
+            section in the Yocto Project Development Tasks Manual.
+        </para>
+    </section>
+
+    <section id='migration-2.6-python-3-profile-guided-optimizations'>
+        <title>Python 3 Profile-Guided Optimization</title>
+
+        <para>
+            The <filename>python3</filename> recipe now enables profile-guided
+            optimization.
+            Using this optimization requires a little extra build time in
+            exchange for improved performance on the target at runtime.
+            Additionally, the optimization is only enabled if the current
+            <link linkend='var-MACHINE'><filename>MACHINE</filename></link>
+            has support for user-mode emulation in QEMU (i.e. "qemu-usermode"
+            is in
+            <link linkend='var-MACHINE_FEATURES'><filename>MACHINE_FEATURES</filename></link>,
+            which it is by default).
+        </para>
+
+        <para>
+            If you wish to disable Python profile-guided optimization
+            regardless of the value of
+            <filename>MACHINE_FEATURES</filename>, then ensure that
+            <link linkend='var-PACKAGECONFIG'><filename>PACKAGECONFIG</filename></link>
+            for the <filename>python3</filename> recipe does not contain "pgo".
+            You could accomplish the latter using the following at the
+            configuration level:
+            <literallayout class='monospaced'>
+     PACKAGECONFIG_remove_pn-python3 = "pgo"
+            </literallayout>
+            Alternatively, you can set
+            <filename>PACKAGECONFIG</filename> using an append file for the
+            <filename>python3</filename> recipe.
+        </para>
+    </section>
+
+    <section id='migration-2.6-miscellaneous-changes'>
+        <title>Miscellaneous Changes</title>
+
+        <para>
+            The following miscellaneous changes occurred:
+            <itemizedlist>
+                <listitem><para>
+                    Default to using the Thumb-2 instruction set for armv7a
+                    and above.
+                    If you have any custom recipes that build software that
+                    needs to be built with the ARM instruction set, change the
+                    recipe to set the instruction set as follows:
+                    <literallayout class='monospaced'>
+     ARM_INSTRUCTION_SET = "arm"
+                    </literallayout>
+                    </para></listitem>
+                <listitem><para>
+                    <filename>run-postinsts</filename> no longer uses
+                    <filename>/etc/*-postinsts</filename> for
+                    <filename>dpkg/opkg</filename> in favor of built-in
+                    postinst support.
+                    RPM behavior remains unchanged.
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>NOISO</filename> and
+                    <filename>NOHDD</filename> variables are no longer used.
+                    You now control building <filename>*.iso</filename> and
+                    <filename>*.hddimg</filename> image types directly
+                    by using the
+                    <link linkend='var-IMAGE_FSTYPES'><filename>IMAGE_FSTYPES</filename></link>
+                    variable.
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>scripts/contrib/mkefidisk.sh</filename>
+                    has been removed in favor of Wic.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>kernel-modules</filename> has been removed from
+                    <link linkend='var-RRECOMMENDS'><filename>RRECOMMENDS</filename></link>
+                    for <filename>qemumips</filename> and
+                    <filename>qemumips64</filename> machines.
+                    Removal also impacts the <filename>x86-base.inc</filename>
+                    file.
+                    <note>
+                        <filename>genericx86</filename> and
+                        <filename>genericx86-64</filename> retain
+                        <filename>kernel-modules</filename> as part of the
+                        <filename>RRECOMMENDS</filename> variable setting.
+                    </note>
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>LGPLv2_WHITELIST_GPL-3.0</filename>
+                    variable has been removed.
+                    If you are setting this variable in your configuration,
+                    set or append it to the
+                    <filename>WHITELIST_GPL-3.0</filename> variable instead.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>${ASNEEDED}</filename> is now included in
+                    the
+                    <link linkend='var-TARGET_LDFLAGS'><filename>TARGET_LDFLAGS</filename></link>
+                    variable directly.
+                    The remaining definitions from
+                    <filename>meta/conf/distro/include/as-needed.inc</filename>
+                    have been moved to corresponding recipes.
+                    </para></listitem>
+                <listitem><para>
+                    Support for DSA host keys has been dropped from the
+                    OpenSSH recipes.
+                    If you are still using DSA keys, you must switch over to a
+                    more secure algorithm as recommended by OpenSSH upstream.
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>dhcp</filename> recipe now uses the
+                    <filename>dhcpd6.conf</filename> configuration file in
+                    <filename>dhcpd6.service</filename> for IPv6 DHCP rather
+                    than re-using <filename>dhcpd.conf</filename>, which is
+                    now reserved for IPv4.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+</section>
+
+<section id='moving-to-the-yocto-project-2.7-release'>
+    <title>Moving to the Yocto Project 2.7 Release</title>
+
+    <para>
+        This section provides migration information for moving to the
+        Yocto Project 2.7 Release from the prior release.
+    </para>
+
+    <section id='migration-2.7-bitbake-changes'>
+        <title>BitBake Changes</title>
+
+        <para>
+            The following changes have been made to BitBake:
+            <itemizedlist>
+                <listitem><para>
+                    BitBake now checks anonymous Python functions and pure
+                    Python functions (e.g. <filename>def funcname:</filename>)
+                    in the metadata for tab indentation.
+                    If found, BitBake  produces a warning.
+                    </para></listitem>
+                <listitem><para>
+                    Bitbake now checks
+                    <link linkend='var-BBFILE_COLLECTIONS'><filename>BBFILE_COLLECTIONS</filename></link>
+                    for duplicate entries and triggers an error if any are
+                    found.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.7-eclipse-support-dropped'>
+        <title><trademark class='trade'>Eclipse</trademark> Support Removed</title>
+
+        <para>
+            Support for the Eclipse IDE has been removed.
+            Support continues for those releases prior to 2.7 that did include
+            support.
+            The 2.7 release does not include the Eclipse Yocto plugin.
+        </para>
+    </section>
+
+    <section id='migration-2.7-qemu-native-splits-system-and-user-mode-parts'>
+        <title><filename>qemu-native</filename> Splits the System and User-Mode Parts</title>
+
+        <para>
+            The system and user-mode parts of <filename>qemu-native</filename>
+            are now split.
+            <filename>qemu-native</filename> provides the user-mode components
+            and <filename>qemu-system-native</filename> provides the system
+            components.
+            If you have recipes that depend on QEMU's system emulation
+            functionality at build time, they should now depend upon
+            <filename>qemu-system-native</filename> instead of
+            <filename>qemu-native</filename>.
+        </para>
+    </section>
+
+    <section id='migration-2.7-upstream-tracking.inc-removed'>
+        <title>The <filename>upstream-tracking.inc</filename> File Has Been Removed</title>
+
+        <para>
+            The previously deprecated <filename>upstream-tracking.inc</filename>
+            file is now removed.
+            Any <filename>UPSTREAM_TRACKING*</filename> variables are now set
+            in the corresponding recipes instead.
+        </para>
+
+        <para>
+            Remove any references you have to the
+            <filename>upstream-tracking.inc</filename> file in your
+            configuration.
+        </para>
+    </section>
+
+    <section id='migration-2.7-distro-features-libc-removed'>
+        <title>The <filename>DISTRO_FEATURES_LIBC</filename> Variable Has Been Removed</title>
+
+        <para>
+            The <filename>DISTRO_FEATURES_LIBC</filename> variable is no
+            longer used.
+            The ability to configure glibc using kconfig has been removed
+            for quite some time making the <filename>libc-*</filename> features
+            set no longer effective.
+        </para>
+
+        <para>
+            Remove any references you have to
+            <filename>DISTRO_FEATURES_LIBC</filename> in your own layers.
+        </para>
+    </section>
+
+    <section id='migration-2.7-license-values'>
+        <title>License Value Corrections</title>
+
+        <para>
+            The following corrections have been made to the
+            <link linkend='var-LICENSE'><filename>LICENSE</filename></link>
+            values set by recipes:
+            <literallayout class='monospaced'>
+     <emphasis>socat</emphasis>: Corrected <filename>LICENSE</filename> to be "GPLv2" rather than
+        "GPLv2+".
+
+     <emphasis>libgfortran</emphasis>: Set license to "GPL-3.0-with-GCC-exception".
+
+     <emphasis>elfutils</emphasis>: Removed "Elfutils-Exception" and set to "GPLv2" for shared
+        libraries
+            </literallayout>
+        </para>
+    </section>
+
+    <section id='migration-2.7-packaging-changes'>
+        <title>Packaging Changes</title>
+
+        <para>
+            This section provides information about packaging changes.
+            <itemizedlist>
+                <listitem><para>
+                    <filename>bind</filename>: The
+                    <filename>nsupdate</filename> binary has been moved to
+                    the <filename>bind-utils</filename> package.
+                    </para></listitem>
+                <listitem><para>
+                    Debug split: The default debug split has been changed to
+                    create separate source packages (i.e.
+                    <replaceable>package_name</replaceable><filename>-dbg</filename>
+                    and
+                    <replaceable>package_name</replaceable><filename>-src</filename>).
+                    If you are currently using <filename>dbg-pkgs</filename>
+                    in
+                    <link linkend='var-IMAGE_FEATURES'><filename>IMAGE_FEATURES</filename></link>
+                    to bring in debug symbols and you still need the sources,
+                    you must now also add <filename>src-pkgs</filename> to
+                    <filename>IMAGE_FEATURES</filename>.
+                    Source packages remain in the target portion of the SDK
+                    by default, unless you have set your own value for
+                    <link linkend='var-SDKIMAGE_FEATURES'><filename>SDKIMAGE_FEATURES</filename></link>
+                    that does not include <filename>src-pkgs</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    Mount all using <filename>util-linux</filename>:
+                    <filename>/etc/default/mountall</filename> has
+                    moved into the -mount sub-package.
+                    </para></listitem>
+                <listitem><para>
+                    Splitting binaries using <filename>util-linux</filename>:
+                    <filename>util-linux</filename> now splits each binary into
+                    its own package for fine-grained control.
+                    The main <filename>util-linux</filename> package pulls in
+                    the individual binary packages using the
+                    <link linkend='var-RRECOMMENDS'><filename>RRECOMMENDS</filename></link>
+                    and
+                    <link linkend='var-RDEPENDS'><filename>RDEPENDS</filename></link>
+                    variables.
+                    As a result, existing images should not see any changes
+                    assuming
+                    <link linkend='var-NO_RECOMMENDATIONS'><filename>NO_RECOMMENDATIONS</filename></link>
+                    is not set.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>netbase/base-files</filename>:
+                    <filename>/etc/hosts</filename> has moved from
+                    <filename>netbase</filename> to
+                    <filename>base-files</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>tzdata</filename>: The main package has been
+                    converted to an empty meta package that pulls in all
+                    <filename>tzdata</filename> packages by default.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>lrzsz</filename>: This package has been removed
+                    from <filename>packagegroup-self-hosted</filename> and
+                    <filename>packagegroup-core-tools-testapps</filename>.
+                    The X/Y/ZModem support is less likely to be needed on
+                    modern systems.
+                    If you are relying on these packagegroups to include the
+                    <filename>lrzsz</filename> package in your image, you
+                    now need to explicitly add the package.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-2.7-removed-recipes'>
+        <title>Removed Recipes</title>
+
+        <para>
+            The following recipes have been removed:
+            <literallayout class='monospaced'>
+     <emphasis>gcc</emphasis>: Drop version 7.3 recipes. Version 8.3 now remains.
+
+     <emphasis>linux-yocto</emphasis>: Drop versions 4.14 and 4.18 recipes. Versions 4.19 and 5.0 remain.
+
+     <emphasis>go</emphasis>: Drop version 1.9 recipes. Versions 1.11 and 1.12 remain.
+
+     <emphasis>xvideo-tests</emphasis>: Became obsolete.
+
+     <emphasis>libart-lgpl</emphasis>: Became obsolete.
+
+     <emphasis>gtk-icon-utils-native</emphasis>: These tools are now provided by gtk+3-native
+
+     <emphasis>gcc-cross-initial</emphasis>: No longer needed. gcc-cross/gcc-crosssdk is now used instead.
+
+     <emphasis>gcc-crosssdk-initial</emphasis>: No longer needed. gcc-cross/gcc-crosssdk is now used instead.
+
+     <emphasis>glibc-initial</emphasis>: Removed because the benefits of having it for site_config are
+        currently outweighed by the cost of building the recipe.
+            </literallayout>
+         </para>
+    </section>
+
+    <section id='migration-2.7-removed-classes'>
+        <title>Removed Classes</title>
+
+        <para>
+            The following classes have been removed:
+            <literallayout class='monospaced'>
+     <emphasis>distutils-tools</emphasis>: This class was never used.
+
+     <emphasis>bugzilla.bbclass</emphasis>: Became obsolete.
+
+     <emphasis>distrodata</emphasis>: This functionally has been replaced by a more modern
+         tinfoil-based implementation.
+            </literallayout>
+        </para>
+    </section>
+
+    <section id='migration-2.7-miscellaneous-changes'>
+        <title>Miscellaneous Changes</title>
+
+        <para>
+            The following miscellaneous changes occurred:
+            <itemizedlist>
+                <listitem><para>
+                    The <filename>distro</filename> subdirectory of the Poky
+                    repository has been removed from the top-level
+                    <filename>scripts</filename> directory.
+                    </para></listitem>
+                <listitem><para>
+                    Perl now builds for the target using
+                    <ulink url='http://arsv.github.io/perl-cross/'><filename>perl-cross</filename></ulink>
+                    for better maintainability and improved build performance.
+                    This change should not present any problems unless you have
+                    heavily customized your Perl recipe.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>arm-tunes</filename>: Removed the "-march"
+                    option if mcpu is already added.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>update-alternatives</filename>: Convert file
+                    renames to
+                    <link linkend='var-PACKAGE_PREPROCESS_FUNCS'><filename>PACKAGE_PREPROCESS_FUNCS</filename></link>
+                    </para></listitem>
+                <listitem><para>
+                    <filename>base/pixbufcache</filename>: Obsolete
+                    <filename>sstatecompletions</filename> code has been
+                    removed.
+                    </para></listitem>
+                <listitem><para>
+                    <link linkend='ref-classes-native'><filename>native</filename></link>
+                    class:
+                    <link linkend='var-RDEPENDS'><filename>RDEPENDS</filename></link>
+                    handling has been enabled.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>inetutils</filename>: This recipe has rsh
+                    disabled.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+</section>
+
+<section id='moving-to-the-yocto-project-3.0-release'>
+    <title>Moving to the Yocto Project 3.0 Release</title>
+
+    <para>
+        This section provides migration information for moving to the
+        Yocto Project 3.0 Release from the prior release.
+    </para>
+
+    <section id='migration-3.0-init-system-selection'>
+        <title>Init System Selection</title>
+
+        <para>
+            Changing the init system manager previously required setting a
+            number of different variables.
+            You can now change the manager by setting the
+            <filename>INIT_MANAGER</filename> variable and the corresponding
+            include files
+            (i.e. <filename>conf/distro/include/init-manager-*.conf</filename>).
+            Include files are provided for four values: "none", "sysvinit",
+            "systemd", and "mdev-busybox".
+            The default value, "none", for <filename>INIT_MANAGER</filename>
+            should allow your current settings to continue working.
+            However, it is advisable to explicitly set
+            <filename>INIT_MANAGER</filename>.
+        </para>
+    </section>
+
+    <section id='migration-3.0-lsb-support-removed'>
+        <title>LSB Support Removed</title>
+
+        <para>
+            Linux Standard Base (LSB) as a standard is not current, and
+            is not well suited for embedded applications.
+            Support can be continued in a separate layer if needed.
+            However, presently LSB support has been removed from the core.
+        </para>
+
+        <para>
+            As a result of this change, the <filename>poky-lsb</filename>
+            derivative distribution configuration that was also used for
+            testing alternative configurations has been replaced with a
+            <filename>poky-altcfg</filename> distribution that has LSB
+            parts removed.
+        </para>
+    </section>
+
+    <section id='migration-3.0-removed-recipes'>
+        <title>Removed Recipes</title>
+
+        <para>
+            The following recipes have been removed.
+            <itemizedlist>
+                <listitem><para>
+                    <filename>core-image-lsb-dev</filename>: Part of removed
+                    LSB support.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>core-image-lsb</filename>: Part of removed
+                    LSB support.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>core-image-lsb-sdk</filename>: Part of removed
+                    LSB support.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>cve-check-tool</filename>: Functionally replaced
+                    by the <filename>cve-update-db</filename> recipe and
+                    <filename>cve-check</filename> class.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>eglinfo</filename>: No longer maintained.
+                    <filename>eglinfo</filename> from
+                    <filename>mesa-demos</filename> is an adequate and
+                    maintained alternative.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>gcc-8.3</filename>: Version 8.3 removed.
+                    Replaced by 9.2.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>gnome-themes-standard</filename>: Only needed
+                    by gtk+ 2.x, which has been removed.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>gtk+</filename>: GTK+ 2 is obsolete and has been
+                    replaced by gtk+3.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>irda-utils</filename>: Has become obsolete.
+                    IrDA support has been removed from the Linux kernel in
+                    version 4.17 and later.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>libnewt-python</filename>:
+                    <filename>libnewt</filename> Python support merged into
+                    main <filename>libnewt</filename> recipe.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>libsdl</filename>: Replaced by newer
+                    <filename>libsdl2</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>libx11-diet</filename>: Became obsolete.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>libxx86dga</filename>: Removed obsolete client
+                    library.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>libxx86misc</filename>: Removed. Library is
+                    redundant.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>linux-yocto</filename>: Version 5.0 removed,
+                    which is now redundant (5.2 / 4.19 present).
+                    </para></listitem>
+                <listitem><para>
+                    <filename>lsbinitscripts</filename>: Part of removed LSB
+                    support.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>lsb</filename>: Part of removed LSB support.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>lsbtest</filename>: Part of removed LSB support.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>openssl10</filename>: Replaced by newer
+                    <filename>openssl</filename> version 1.1.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>packagegroup-core-lsb</filename>: Part of removed
+                    LSB support.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>python-nose</filename>: Removed the Python 2.x
+                    version of the recipe.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>python-numpy</filename>: Removed the Python 2.x
+                    version of the recipe.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>python-scons</filename>: Removed the Python 2.x
+                    version of the recipe.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>source-highlight</filename>: No longer needed.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>stress</filename>: Replaced by
+                    <filename>stress-ng</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>vulkan</filename>: Split into
+                    <filename>vulkan-loader</filename>,
+                    <filename>vulkan-headers</filename>, and
+                    <filename>vulkan-tools</filename>.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>weston-conf</filename>: Functionality moved to
+                    <filename>weston-init</filename>.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-3.0-packaging-changes'>
+        <title>Packaging Changes</title>
+
+        <para>
+            The following packaging changes have occurred.
+            <itemizedlist>
+                <listitem><para>
+                    The
+                    <ulink url='https://en.wikipedia.org/wiki/GNOME_Web'>Epiphany</ulink>
+                    browser has been dropped from
+                    <filename>packagegroup-self-hosted</filename> as it has
+                    not been needed inside
+                    <filename>build-appliance-image</filename> for
+                    quite some time and was causing resource problems.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>libcap-ng</filename> Python support has been
+                    moved to a separate <filename>libcap-ng-python</filename>
+                    recipe to streamline the build process when the Python
+                    bindings are not needed.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>libdrm</filename> now packages the file
+                    <filename>amdgpu.ids</filename> into a separate
+                    <filename>libdrm-amdgpu</filename> package.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>python3</filename>: The
+                    <filename>runpy</filename> module is now in the
+                    <filename>python3-core</filename> package as it is
+                    required to support the common "python3 -m" command usage.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>distcc</filename> now provides separate
+                    <filename>distcc-client</filename> and
+                    <filename>distcc-server</filename> packages as typically
+                    one or the other are needed, rather than both.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>python*-setuptools</filename> recipes now
+                    separately package the <filename>pkg_resources</filename>
+                    module in a <filename>python-pkg-resources</filename> /
+                    <filename>python3-pkg-resources</filename> package as
+                    the module is useful independent of the rest of the
+                    setuptools package.
+                    The main <filename>python-setuptools</filename> /
+                    <filename>python3-setuptools</filename> package depends
+                    on this new package so you should only need to update
+                    dependencies unless you want to take advantage of the
+                    increased granularity.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-3.0-cve-checking'>
+        <title>CVE Checking</title>
+
+        <para>
+            <filename>cve-check-tool</filename> has been functionally replaced
+            by a new <filename>cve-update-db</filename> recipe and
+            functionality built into the <filename>cve-check</filename> class.
+            The result uses NVD JSON data feeds rather than the deprecated
+            XML feeds that <filename>cve-check-tool</filename> was using,
+            supports CVSSv3 scoring, and makes other improvements.
+        </para>
+
+        <para>
+            Additionally, the <filename>CVE_CHECK_CVE_WHITELIST</filename>
+            variable has been replaced by
+            <filename>CVE_CHECK_WHITELIST</filename>.
+        </para>
+    </section>
+
+    <section id='migration-3.0-bitbake-changes'>
+        <title>Bitbake Changes</title>
+
+        <para>
+            The following BitBake changes have occurred.
+            <itemizedlist>
+                <listitem><para>
+                    <filename>addtask</filename> statements now properly
+                    validate dependent tasks.
+                    Previously, an invalid task was silently ignored.
+                    With this change, the invalid task generates a warning.
+                    </para></listitem>
+                <listitem><para>
+                    Other invalid <filename>addtask</filename> and
+                    <filename>deltask</filename> usages now trigger these
+                    warnings: "multiple target tasks arguments with
+                    addtask / deltask", and "multiple before/after clauses".
+                    </para></listitem>
+                <listitem><para>
+                    The "multiconfig" prefix is now shortened to "mc".
+                    "multiconfig" will continue to work, however it may be
+                    removed in a future release.
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>bitbake -g</filename> command no longer
+                    generates a <filename>recipe-depends.dot</filename> file
+                    as the contents (i.e. a reprocessed version of
+                    <filename>task-depends.dot</filename>) were confusing.
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>bb.build.FuncFailed</filename> exception,
+                    previously raised by
+                    <filename>bb.build.exec_func()</filename> when certain
+                    other exceptions have occurred, has been removed.
+                    The real underlying exceptions will be raised instead.
+                    If you have calls to
+                    <filename>bb.build.exec_func()</filename> in custom classes
+                    or <filename>tinfoil-using</filename> scripts, any
+                    references to <filename>bb.build.FuncFailed</filename>
+                    should be cleaned up.
+                    </para></listitem>
+                <listitem><para>
+                    Additionally, the
+                    <filename>bb.build.exec_func()</filename> no longer accepts
+                    the "pythonexception" parameter.
+                    The function now always raises exceptions.
+                    Remove this argument in any calls to
+                    <filename>bb.build.exec_func()</filename> in custom classes
+                    or scripts.
+                    </para></listitem>
+                <listitem><para>
+                    The
+                    <ulink url='&YOCTO_DOCS_BB_URL;#var-bb-BB_SETSCENE_VERIFY_FUNCTION2'><filename>BB_SETSCENE_VERIFY_FUNCTION2</filename></ulink>
+                    is no longer used.
+                    In the unlikely event that you have any references to it,
+                    they should be removed.
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>RunQueueExecuteScenequeue</filename> and
+                    <filename>RunQueueExecuteTasks</filename> events have been
+                    removed since setscene tasks are now executed as part of
+                    the normal runqueue.
+                    Any event handling code in custom classes or scripts that
+                    handles these two events need to be updated.
+                    </para></listitem>
+                <listitem><para>
+                    The arguments passed to functions used with
+                    <ulink url='&YOCTO_DOCS_BB_URL;#var-bb-BB_HASHCHECK_FUNCTION'><filename>BB_HASHCHECK_FUNCTION</filename></ulink>
+                    have changed.
+                    If you are using your own custom hash check function, see
+                    <ulink url='http://git.yoctoproject.org/cgit/cgit.cgi/poky/commit/?id=40a5e193c4ba45c928fccd899415ea56b5417725'></ulink>
+                    for details.
+                    </para></listitem>
+                <listitem><para>
+                    Task specifications in <filename>BB_TASKDEPDATA</filename>
+                    and class implementations used in signature generator
+                    classes now use "&lt;fn&gt;:&lt;task&gt;" everywhere rather than
+                    the "." delimiter that was being used in some places.
+                    This change makes it consistent with all areas in the code.
+                    Custom signature generator classes and code that reads
+                    <filename>BB_TASKDEPDATA</filename> need to be updated to
+                    use ':' as a separator rather than '.'.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-3.0-sanity-checks'>
+        <title>Sanity Checks</title>
+
+        <para>
+            The following sanity check changes occurred.
+            <itemizedlist>
+                <listitem><para>
+                    <link linkend='var-SRC_URI'><filename>SRC_URI</filename></link>
+                    is now checked for usage of two problematic items:
+                    <itemizedlist>
+                        <listitem><para>
+                            "${PN}" prefix/suffix use - Warnings always appear
+                            if ${PN} is used.
+                            You must fix the issue regardless of whether
+                            multiconfig or anything else that would cause
+                            prefixing/suffixing to happen.
+                            </para></listitem>
+                        <listitem><para>
+                            Github archive tarballs - these are not guaranteed
+                            to be stable.
+                            Consequently, it is likely that the tarballs will
+                            be refreshed and thus the SRC_URI checksums
+                            will fail to apply.
+                            It is recommended that you fetch either an official
+                            release tarball or a specific revision from the
+                            actual Git repository instead.
+                            </para></listitem>
+                    </itemizedlist>
+                    Either one of these items now trigger a warning by default.
+                    If you wish to disable this check, remove
+                    <filename>src-uri-bad</filename> from
+                    <link linkend='var-WARN_QA'><filename>WARN_QA</filename></link>.
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>file-rdeps</filename> runtime dependency
+                    check no longer expands
+                    <link linkend='var-RDEPENDS'><filename>RDEPENDS</filename></link>
+                    recursively as there is no mechanism to ensure they can be
+                    fully computed, and thus races sometimes result in errors
+                    either showing up or not.
+                    Thus, you might now see errors for missing runtime
+                    dependencies that were previously satisfied recursively.
+                    Here is an example: package A contains a shell script
+                    starting with <filename>#!/bin/bash</filename> but has no
+                    dependency on bash.
+                    However, package A depends on package B, which does depend
+                    on bash.
+                    You need to add the missing dependency or dependencies to
+                    resolve the warning.
+                    </para></listitem>
+                <listitem><para>
+                    Setting <filename>DEPENDS_${PN}</filename> anywhere
+                    (i.e. typically in a recipe) now triggers an error.
+                    The error is triggered because
+                    <link linkend='var-DEPENDS'><filename>DEPENDS</filename></link>
+                    is not a package-specific variable unlike RDEPENDS.
+                    You should set <filename>DEPENDS</filename> instead.
+                    </para></listitem>
+                <listitem><para>
+                    systemd currently does not work well with the musl C
+                    library because only upstream officially supports linking
+                    the library with glibc.
+                    Thus, a warning is shown when building systemd in
+                    conjunction with musl.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-3.0-miscellaneous-changes'>
+        <title>Miscellaneous Changes</title>
+
+        <para>
+            The following miscellaneous changes have occurred.
+            <itemizedlist>
+                <listitem><para>
+                    The <filename>gnome</filename>
+                    class has been removed because it now does very little.
+                    You should update recipes that previously inherited this
+                    class to do the following:
+                    <literallayout class='monospaced'>
+     inherit gnomebase gtk-icon-cache gconf mime
+                    </literallayout>
+                    </para></listitem>
+                <listitem><para>
+                    The
+                    <filename>meta/recipes-kernel/linux/linux-dtb.inc</filename>
+                    file has been removed.
+                    This file was previously deprecated in favor of setting
+                    <link linkend='var-KERNEL_DEVICETREE'><filename>KERNEL_DEVICETREE</filename></link>
+                    in any kernel recipe and only produced a warning.
+                    Remove any <filename>include</filename> or
+                    <filename>require</filename> statements pointing to this
+                    file.
+                    </para></listitem>
+                <listitem><para>
+                    <link linkend='var-TARGET_CFLAGS'><filename>TARGET_CFLAGS</filename></link>,
+                    <link linkend='var-TARGET_CPPFLAGS'><filename>TARGET_CPPFLAGS</filename></link>,
+                    <link linkend='var-TARGET_CXXFLAGS'><filename>TARGET_CXXFLAGS</filename></link>,
+                    and
+                    <link linkend='var-TARGET_LDFLAGS'><filename>TARGET_LDFLAGS</filename></link>
+                    are no longer exported to the external environment.
+                    This change did not require any changes to core recipes,
+                    which is a good indicator that no changes will be
+                    required.
+                    However, if for some reason the software being built by one
+                    of your recipes is expecting these variables to be set,
+                    then building the recipe will fail.
+                    In such cases, you must either export the variable or
+                    variables in the recipe or change the scripts so that
+                    exporting is not necessary.
+                    </para></listitem>
+                <listitem><para>
+                    You must change the host distro identifier used in
+                    <link linkend='var-NATIVELSBSTRING'><filename>NATIVELSBSTRING</filename></link>
+                    to use all lowercase characters even if it does not contain
+                    a version number.
+                    This change is necessary only if you are not using
+                    <filename>uninative</filename> and
+                    <link linkend='var-SANITY_TESTED_DISTROS'><filename>SANITY_TESTED_DISTROS</filename></link>.
+                    </para></listitem>
+                <listitem><para>
+                    In the <filename>base-files</filename> recipe, writing the
+                    hostname into <filename>/etc/hosts</filename> and
+                    <filename>/etc/hostname</filename> is now done within the
+                    main
+                    <link linkend='ref-tasks-install'><filename>do_install</filename></link>
+                    function rather than in the
+                    <filename>do_install_basefilesissue</filename> function.
+                    The reason for the change is because
+                    <filename>do_install_basefilesissue</filename> is more
+                    easily overridden without having to duplicate the hostname
+                    functionality.
+                    If you have done the latter (e.g. in a
+                    <filename>base-files</filename> bbappend), then you should
+                    remove it from your customized
+                    <filename>do_install_basefilesissue</filename> function.
+                    </para></listitem>
+                <listitem><para>
+                    The <filename>wic --expand</filename> command now uses
+                    commas to separate "key:value" pairs rather than hyphens.
+                    <note>
+                        The wic command-line help is not updated.
+                    </note>
+                    You must update any scripts or commands where you use
+                    <filename>wic --expand</filename> with multiple
+                    "key:value" pairs.
+                    </para></listitem>
+                <listitem><para>
+                    UEFI image variable settings have been moved from various
+                    places to a central
+                    <filename>conf/image-uefi.conf</filename>.
+                    This change should not influence any existing configuration
+                    as the <filename>meta/conf/image-uefi.conf</filename>
+                    in the core metadata sets defaults that can be overridden
+                    in the same manner as before.
+                    </para></listitem>
+                <listitem><para>
+                    <filename>conf/distro/include/world-broken.inc</filename>
+                    has been removed.
+                    For cases where certain recipes need to be disabled when
+                    using the musl C library, these recipes now have
+                    <filename>COMPATIBLE_HOST_libc-musl</filename> set with a
+                    comment that explains why.
+                    </para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+</section>
+
+
+<section id='moving-to-the-yocto-project-3.1-release'>
+    <title>Moving to the Yocto Project 3.1 Release</title>
+
+    <para>
+        This section provides migration information for moving to the
+        Yocto Project 3.1 Release from the prior release.
+    </para>
+
+    <section id='migration-3.1-minimum-system-requirements'>
+        <title>Minimum system requirements</title>
+
+        <para>
+            The following versions / requirements of build host components have been updated:
+            <itemizedlist>
+                <listitem><para>gcc 5.0</para></listitem>
+                <listitem><para>python 3.5</para></listitem>
+                <listitem><para>tar 1.28</para></listitem>
+                <listitem><para><filename>rpcgen</filename> is now required on the host (part of the <filename>libc-dev-bin</filename> package on Ubuntu, Debian and related distributions, and the <filename>glibc</filename> package on RPM-based distributions).</para></listitem>
+            </itemizedlist>
+            
+            Additionally, the <filename>makeinfo</filename> and <filename>pod2man</filename>
+            tools are <emphasis>no longer</emphasis> required on the host.
+        </para>
+    </section>
+
+    <section id='migration-3.1-mpc8315e-rdb-removed'>
+        <title>mpc8315e-rdb machine removed</title>
+
+        <para>
+            The MPC8315E-RDB machine is old/obsolete and unobtainable, thus given the maintenance burden
+            the <filename>mpc8315e-rdb</filename> machine configuration that supported it has been removed
+            in this release. The removal does leave a gap in official PowerPC reference hardware
+            support; this may change in future if a suitable machine with accompanying support resources
+            is found.
+        </para>
+    </section>
+    
+    <section id='migration-3.1-python-2-removed'>
+        <title>Python 2 removed</title>
+
+        <para>
+            Due to the expiration of upstream support in January 2020, support for Python 2 has now been removed; it is recommended that you use Python 3 instead. If absolutely needed there is a meta-python2 community layer containing Python 2, related classes and various Python 2-based modules, however it should not be considered as supported.
+        </para>
+    </section>
+
+    <section id='migration-3.1-reproducible-builds'>
+        <title>Reproducible builds now enabled by default</title>
+
+        <para>
+            In order to avoid unnecessary differences in output files (aiding binary reproducibility), the Poky distribution configuration (<filename><link linkend='var-DISTRO'>DISTRO</link> = "poky"</filename>) now inherits the <filename>reproducible_build</filename> class by default.
+        </para>
+    </section>
+    
+    <section id='migration-3.1-ptest-feature-impact'>
+        <title>Impact of ptest feature is now more significant</title>
+
+        <para>
+            The Poky distribution configuration (<filename><link linkend='var-DISTRO'>DISTRO</link> = "poky"</filename>) enables ptests by default to enable runtime testing of various components. In this release, a dependency needed to be added that has resulted in a significant increase in the number of components that will be built just when building a simple image such as core-image-minimal. If you do not need runtime tests enabled for core components, then it is recommended that you remove "ptest" from <link linkend='var-DISTRO_FEATURES'><filename>DISTRO_FEATURES</filename></link> to save a significant amount of build time e.g. by adding the following in your configuration:
+
+            <literallayout class='monospaced'>
+      DISTRO_FEATURES_remove = "ptest"
+            </literallayout>
+        </para>
+    </section>
+
+    <section id='migration-3.1-removed-recipes'>
+        <title>Removed recipes</title>
+
+        <para>
+            The following recipes have been removed:
+
+            <itemizedlist>
+                <listitem><para><filename>chkconfig</filename>: obsolete</para></listitem>
+                <listitem><para><filename>console-tools</filename>: obsolete</para></listitem>
+                <listitem><para><filename>enchant</filename>: replaced by <filename>enchant2</filename></para></listitem>
+                <listitem><para><filename>foomatic-filters</filename>: obsolete</para></listitem>
+                <listitem><para><filename>libidn</filename>: no longer needed, moved to meta-oe</para></listitem>
+                <listitem><para><filename>libmodulemd</filename>: replaced by <filename>libmodulemd-v1</filename></para></listitem>
+                <listitem><para><filename>linux-yocto</filename>: drop 4.19, 5.2 version recipes (5.4 now provided)</para></listitem>
+                <listitem><para><filename>nspr</filename>: no longer needed, moved to meta-oe</para></listitem>
+                <listitem><para><filename>nss</filename>: no longer needed, moved to meta-oe</para></listitem>
+                <listitem><para><filename>python</filename>: Python 2 removed (Python 3 preferred)</para></listitem>
+                <listitem><para><filename>python-setuptools</filename>: Python 2 version removed (python3-setuptools preferred)</para></listitem>
+                <listitem><para><filename>sysprof</filename>: no longer needed, moved to meta-oe</para></listitem>
+                <listitem><para><filename>texi2html</filename>: obsolete</para></listitem>
+                <listitem><para><filename>u-boot-fw-utils</filename>: functionally replaced by <filename>libubootenv</filename></para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-3.1-features-check'>
+        <title>features_check class replaces distro_features_check</title>
+
+        <para>
+            The <filename>distro_features_check</filename> class has had its functionality expanded, now supporting <filename>ANY_OF_MACHINE_FEATURES</filename>, <filename>REQUIRED_MACHINE_FEATURES</filename>, <filename>CONFLICT_MACHINE_FEATURES</filename>, <filename>ANY_OF_COMBINED_FEATURES</filename>, <filename>REQUIRED_COMBINED_FEATURES</filename>, <filename>CONFLICT_COMBINED_FEATURES</filename>. As a result the class has now been renamed to <filename>features_check</filename>; the <filename>distro_features_check</filename> class still exists but generates a warning and redirects to the new class. In preparation for a future removal of the old class it is recommended that you update recipes currently inheriting <filename>distro_features_check</filename> to inherit <filename>features_check</filename> instead.
+        </para>
+    </section>
+
+    <section id='migration-3.1-removed-classes'>
+        <title>Removed classes</title>
+
+        <para>
+            The following classes have been removed:
+
+            <itemizedlist>
+                <listitem><para><filename>distutils-base</filename>: moved to meta-python2</para></listitem>
+                <listitem><para><filename>distutils</filename>: moved to meta-python2</para></listitem>
+                <listitem><para><filename>libc-common</filename>: merged into the glibc recipe as nothing else used it.</para></listitem>
+                <listitem><para><filename>python-dir</filename>: moved to meta-python2</para></listitem>
+                <listitem><para><filename>pythonnative</filename>: moved to meta-python2</para></listitem>
+                <listitem><para><filename>setuptools</filename>: moved to meta-python2</para></listitem>
+                <listitem><para><filename>tinderclient</filename>: dropped as it was obsolete.</para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+    <section id='migration-3.1-src-uri-checksums'>
+        <title>SRC_URI checksum behaviour</title>
+
+        <para>
+            Previously, recipes by tradition included both SHA256 and MD5 checksums for remotely fetched files in <link linkend='var-SRC_URI'><filename>SRC_URI</filename></link>, even though only one is actually mandated. However, the MD5 checksum does not add much given its inherent weakness; thus when a checksum fails only the SHA256 sum will now be printed. The md5sum will still be verified if it is specified.
+        </para>
+    </section>
+
+
+    <section id='migration-3.1-npm'>
+        <title>npm fetcher changes</title>
+
+        <para>
+            The npm fetcher has been completely reworked in this release. The npm fetcher now only fetches the package source itself and no longer the dependencies; there is now also an npmsw fetcher which explicitly fetches the shrinkwrap file and the dependencies. This removes the slightly awkward <filename>NPM_LOCKDOWN</filename> and <filename>NPM_SHRINKWRAP</filename> variables which pointed to local files; the lockdown file is no longer needed at all. Additionally, the package name in <filename>npm://</filename> entries in <link linkend='var-SRC_URI'><filename>SRC_URI</filename></link> is now specified using a <filename>package</filename> parameter instead of the earlier <filename>name</filename> which overlapped with the generic <filename>name</filename> parameter. All recipes using the npm fetcher will need to be changed as a result. 
+        </para>
+        <para>
+            An example of the new scheme:
+            <literallayout class='monospaced'>
+SRC_URI = "npm://registry.npmjs.org;package=array-flatten;version=1.1.1 \
+           npmsw://${THISDIR}/npm-shrinkwrap.json"
+            </literallayout>
+            Another example where the sources are fetched from git rather than an npm repository:
+            <literallayout class='monospaced'>
+SRC_URI = "git://github.com/foo/bar.git;protocol=https \
+           npmsw://${THISDIR}/npm-shrinkwrap.json"
+            </literallayout>
+        </para>
+        <para>
+            devtool and recipetool have also been updated to match with the npm fetcher changes. Other than producing working and more complete recipes for npm sources, there is also a minor change to the command line for devtool: the <filename>--fetch-dev</filename> option has been renamed to <filename>--npm-dev</filename> as it is npm-specific.
+        </para>
+    </section>
+    
+    
+    <section id='migration-3.1-packaging-changes'>
+        <title>Packaging changes</title>
+
+        <para>
+            <itemizedlist>
+                <listitem><para><filename>intltool</filename> has been removed from <filename>packagegroup-core-sdk</filename> as it is rarely needed to build modern software - gettext can do most of the things it used to be needed for. <filename>intltool</filename> has also been removed from <filename>packagegroup-core-self-hosted</filename> as it is not needed to for standard builds.</para></listitem>
+                <listitem><para>git: <filename>git-am</filename>, <filename>git-difftool</filename>, <filename>git-submodule</filename>, and <filename>git-request-pull</filename> are no longer perl-based, so are now installed with the main <filename>git</filename> package instead of within <filename>git-perltools</filename>.</para></listitem>
+                <listitem><para>The <filename>ldconfig</filename> binary built as part of glibc has now been moved to its own <filename>ldconfig</filename> package (note no <filename>glibc-</filename> prefix). This package is in the <link linkend='var-RRECOMMENDS'><filename>RRECOMMENDS</filename></link> of the main <filename>glibc</filename> package if <filename>ldconfig</filename> is present in <link linkend='var-DISTRO_FEATURES'><filename>DISTRO_FEATURES</filename></link>.</para></listitem>
+                <listitem><para><filename>libevent</filename> now splits each shared library into its own package (as Debian does). Since these are shared libraries and will be pulled in through the normal shared library dependency handling, there should be no impact to existing configurations other than less unnecessary libraries being installed in some cases.</para></listitem>
+                <listitem><para>linux-firmware now has a new package for <filename>bcm4366c</filename> and includes available NVRAM config files into the <filename>bcm43340</filename>, <filename>bcm43362</filename>, <filename>bcm43430</filename> and <filename>bcm4356-pcie</filename> packages.</para></listitem>
+                <listitem><para><filename>harfbuzz</filename> now splits the new <filename>libharfbuzz-subset.so</filename> library into its own package to reduce the main package size in cases where <filename>libharfbuzz-subset.so</filename> is not needed.</para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+    
+    <section id='migration-3.1-package-qa-warnings'>
+        <title>Additional warnings</title>
+
+        <para>
+            Warnings will now be shown at <filename>do_package_qa</filename> time in the following circumstances:
+            
+            <itemizedlist>
+                <listitem><para>A recipe installs <filename>.desktop</filename> files containing <filename>MimeType</filename> keys but does not inherit the new <filename>mime-xdg</filename> class</para></listitem>
+                <listitem><para>A recipe installs <filename>.xml</filename> files into <filename>${datadir}/mime/packages</filename> but does not inherit the <filename>mime</filename> class</para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+        
+    <section id='migration-3.1-x86-live-wic'>
+        <title><filename>wic</filename> image type now used instead of <filename>live</filename> by default for x86</title>
+
+        <para>
+            <filename>conf/machine/include/x86-base.inc</filename> (inherited by most x86 machine configurations) now specifies <filename>wic</filename> instead of <filename>live</filename> by default in <link linkend='var-IMAGE_FSTYPES'><filename>IMAGE_FSTYPES</filename></link>. The <filename>live</filename> image type will likely be removed in a future release so it is recommended that you use <filename>wic</filename> instead.
+        </para>
+    </section>
+                
+    <section id='migration-3.1-misc'>
+        <title>Miscellaneous changes</title>
+
+        <para>
+            <itemizedlist>
+                <listitem><para>The undocumented <filename>SRC_DISTRIBUTE_LICENSES</filename> variable has now been removed in favour of a new <filename>AVAILABLE_LICENSES</filename> variable which is dynamically set based upon license files found in <filename>${COMMON_LICENSE_DIR}</filename> and <filename>${LICENSE_PATH}</filename>.</para></listitem>
+                <listitem><para>The tune definition for big-endian microblaze machines is now <filename>microblaze</filename> instead of <filename>microblazeeb</filename>.</para></listitem>
+                <listitem><para><filename>newlib</filename> no longer has built-in syscalls. <filename>libgloss</filename> should then provide the syscalls, <filename>crt0.o</filename> and other functions that are no longer part of <filename>newlib</filename> itself. If you are using <filename>TCLIBC = "newlib"</filename> this now means that you must link applications with both <filename>newlib</filename> and <filename>libgloss</filename>, whereas before <filename>newlib</filename> would run in many configurations by itself.</para></listitem>
+            </itemizedlist>
+        </para>
+    </section>
+
+</section>
+
+
+</chapter>
+<!--
+vim: expandtab tw=80 ts=4
+-->