diff --git a/poky/bitbake/lib/bb/parse/__init__.py b/poky/bitbake/lib/bb/parse/__init__.py
index 5397d57..76e180b 100644
--- a/poky/bitbake/lib/bb/parse/__init__.py
+++ b/poky/bitbake/lib/bb/parse/__init__.py
@@ -9,20 +9,10 @@
 # Copyright (C) 2003, 2004  Chris Larson
 # Copyright (C) 2003, 2004  Phil Blundell
 #
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License version 2 as
-# published by the Free Software Foundation.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License along
-# with this program; if not, write to the Free Software Foundation, Inc.,
-# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+# SPDX-License-Identifier: GPL-2.0-only
 #
 # Based on functions from the base bb module, Copyright 2003 Holger Schurig
+#
 
 handlers = []
 
diff --git a/poky/bitbake/lib/bb/parse/ast.py b/poky/bitbake/lib/bb/parse/ast.py
index 6d7c80b..f0911e6 100644
--- a/poky/bitbake/lib/bb/parse/ast.py
+++ b/poky/bitbake/lib/bb/parse/ast.py
@@ -1,5 +1,3 @@
-# ex:ts=4:sw=4:sts=4:et
-# -*- tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*-
 """
  AbstractSyntaxTree classes for the Bitbake language
 """
@@ -8,19 +6,8 @@
 # Copyright (C) 2003, 2004 Phil Blundell
 # Copyright (C) 2009 Holger Hans Peter Freyther
 #
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License version 2 as
-# published by the Free Software Foundation.
+# SPDX-License-Identifier: GPL-2.0-only
 #
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License along
-# with this program; if not, write to the Free Software Foundation, Inc.,
-# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
-
 
 import re
 import string
diff --git a/poky/bitbake/lib/bb/parse/parse_py/BBHandler.py b/poky/bitbake/lib/bb/parse/parse_py/BBHandler.py
index 9dba5f2..889f230 100644
--- a/poky/bitbake/lib/bb/parse/parse_py/BBHandler.py
+++ b/poky/bitbake/lib/bb/parse/parse_py/BBHandler.py
@@ -1,6 +1,4 @@
 #!/usr/bin/env python
-# ex:ts=4:sw=4:sts=4:et
-# -*- tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*-
 """
    class for handling .bb files
 
@@ -12,19 +10,8 @@
 #  Copyright (C) 2003, 2004  Chris Larson
 #  Copyright (C) 2003, 2004  Phil Blundell
 #
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License version 2 as
-# published by the Free Software Foundation.
+# SPDX-License-Identifier: GPL-2.0-only
 #
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License along
-# with this program; if not, write to the Free Software Foundation, Inc.,
-# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
-
 
 import re, bb, os
 import logging
@@ -42,7 +29,7 @@
 __inherit_regexp__       = re.compile(r"inherit\s+(.+)" )
 __export_func_regexp__   = re.compile(r"EXPORT_FUNCTIONS\s+(.+)" )
 __addtask_regexp__       = re.compile(r"addtask\s+(?P<func>\w+)\s*((before\s*(?P<before>((.*(?=after))|(.*))))|(after\s*(?P<after>((.*(?=before))|(.*)))))*")
-__deltask_regexp__       = re.compile(r"deltask\s+(?P<func>\w+)")
+__deltask_regexp__       = re.compile(r"deltask\s+(?P<func>\w+)(?P<ignores>.*)")
 __addhandler_regexp__    = re.compile(r"addhandler\s+(.+)" )
 __def_regexp__           = re.compile(r"def\s+(\w+).*:" )
 __python_func_regexp__   = re.compile(r"(\s+.*)|(^$)|(^#)" )
@@ -236,11 +223,27 @@
 
     m = __addtask_regexp__.match(s)
     if m:
+        if len(m.group().split()) == 2:
+            # Check and warn for "addtask task1 task2"
+            m2 = re.match(r"addtask\s+(?P<func>\w+)(?P<ignores>.*)", s)
+            if m2 and m2.group('ignores'):
+                logger.warning('addtask ignored: "%s"' % m2.group('ignores'))
+
+        # Check and warn for "addtask task1 before task2 before task3", the
+        # similar to "after"
+        taskexpression = s.split()
+        for word in ('before', 'after'):
+            if taskexpression.count(word) > 1:
+                logger.warning("addtask contained multiple '%s' keywords, only one is supported" % word)
+
         ast.handleAddTask(statements, fn, lineno, m)
         return
 
     m = __deltask_regexp__.match(s)
     if m:
+        # Check and warn "for deltask task1 task2"
+        if m.group('ignores'):
+            logger.warning('deltask ignored: "%s"' % m.group('ignores'))
         ast.handleDelTask(statements, fn, lineno, m)
         return
 
diff --git a/poky/bitbake/lib/bb/parse/parse_py/ConfHandler.py b/poky/bitbake/lib/bb/parse/parse_py/ConfHandler.py
index ea49f8c..71bf61b 100644
--- a/poky/bitbake/lib/bb/parse/parse_py/ConfHandler.py
+++ b/poky/bitbake/lib/bb/parse/parse_py/ConfHandler.py
@@ -1,6 +1,4 @@
 #!/usr/bin/env python
-# ex:ts=4:sw=4:sts=4:et
-# -*- tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*-
 """
    class for handling configuration data files
 
@@ -11,18 +9,8 @@
 # Copyright (C) 2003, 2004  Chris Larson
 # Copyright (C) 2003, 2004  Phil Blundell
 #
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License version 2 as
-# published by the Free Software Foundation.
+# SPDX-License-Identifier: GPL-2.0-only
 #
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License along
-# with this program; if not, write to the Free Software Foundation, Inc.,
-# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 
 import errno
 import re
diff --git a/poky/bitbake/lib/bb/parse/parse_py/__init__.py b/poky/bitbake/lib/bb/parse/parse_py/__init__.py
index 3e658d0..cdebe44 100644
--- a/poky/bitbake/lib/bb/parse/parse_py/__init__.py
+++ b/poky/bitbake/lib/bb/parse/parse_py/__init__.py
@@ -1,6 +1,4 @@
 #!/usr/bin/env python
-# ex:ts=4:sw=4:sts=4:et
-# -*- tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*-
 """
 BitBake Parsers
 
@@ -11,20 +9,10 @@
 # Copyright (C) 2003, 2004  Chris Larson
 # Copyright (C) 2003, 2004  Phil Blundell
 #
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License version 2 as
-# published by the Free Software Foundation.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License along
-# with this program; if not, write to the Free Software Foundation, Inc.,
-# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+# SPDX-License-Identifier: GPL-2.0-only
 #
 # Based on functions from the base bb module, Copyright 2003 Holger Schurig
+#
 
 from __future__ import absolute_import
 from . import ConfHandler