diff --git a/ci/Dockerfile/ubuntu2004 b/ci/Dockerfile/ubuntu2004
index 32ee033..3d64210 100644
--- a/ci/Dockerfile/ubuntu2004
+++ b/ci/Dockerfile/ubuntu2004
@@ -2,9 +2,9 @@
 # Don't ask. Ubuntu is awful.
 RUN sed -e 's/main$/main universe/' --in-place=orig /etc/apt/sources.list
 RUN DEBIAN_FRONTEND=noninteractive apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -yy cscope ctags libz-dev libexpat-dev \
-          python language-pack-en texinfo gawk cpio xxd \
+          python-is-python3 language-pack-en texinfo gawk cpio xxd \
           build-essential g++ git bison flex unzip \
           libssl-dev libxml-simple-perl libxml-sax-perl libxml-parser-perl libxml2-dev libxml2-utils xsltproc \
           wget bc rsync
-RUN DEBIAN_FRONTEND=noninteractive apt-get -y install eatmydata python-matplotlib \
-          python-numpy graphviz bsdmainutils lsb-release
+RUN DEBIAN_FRONTEND=noninteractive apt-get -y install eatmydata python3-matplotlib \
+          python3-scipy graphviz bsdmainutils lsb-release