diff --git a/docker/base.Dockerfile b/docker/base.Dockerfile
index e2465f33c2..f364456c7a 100644
--- a/docker/base.Dockerfile
+++ b/docker/base.Dockerfile
@@ -1,4 +1,4 @@
-FROM python:3.9-bullseye
+FROM python:3.9-bookworm
 LABEL maintainer="IETF Tools Team <tools-discuss@ietf.org>"
 
 ENV DEBIAN_FRONTEND=noninteractive
@@ -14,6 +14,9 @@ RUN apt-get install -y --no-install-recommends ca-certificates curl gnupg \
     && mkdir -p /etc/apt/keyrings\
     && curl -fsSL https://deb.nodesource.com/gpgkey/nodesource-repo.gpg.key | gpg --dearmor -o /etc/apt/keyrings/nodesource.gpg
 RUN echo "deb [signed-by=/etc/apt/keyrings/nodesource.gpg] https://deb.nodesource.com/node_$NODE_MAJOR.x nodistro main" | tee /etc/apt/sources.list.d/nodesource.list
+RUN echo "Package: nodejs" >> /etc/apt/preferences.d/preferences && \
+    echo "Pin: origin deb.nodesource.com" >> /etc/apt/preferences.d/preferences && \
+    echo "Pin-Priority: 1001" >> /etc/apt/preferences.d/preferences
 
 # Add Docker Source
 RUN curl -fsSL https://download.docker.com/linux/debian/gpg | gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg
@@ -56,12 +59,13 @@ RUN apt-get update --fix-missing && apt-get install -qy --no-install-recommends
 	libmagic-dev \
 	libmariadb-dev \
 	libmemcached-tools \
+	libyang2-tools \
 	locales \
 	make \
 	mariadb-client \
 	memcached \
 	nano \
-	netcat \
+	netcat-traditional \
 	nodejs \
 	pgloader \
 	pigz \
@@ -77,7 +81,6 @@ RUN apt-get update --fix-missing && apt-get install -qy --no-install-recommends
 	wget \
 	xauth \
 	xvfb \
-	yang-tools \
 	zsh
 
 # Install kramdown-rfc2629 (ruby)
@@ -106,11 +109,11 @@ RUN apt-get autoremove -y && apt-get clean -y && rm -rf /var/lib/apt/lists/* /va
 ENV DBUS_SESSION_BUS_ADDRESS=/dev/null
 
 # avoid million NPM install messages
-ENV npm_config_loglevel warn
+ENV npm_config_loglevel=warn
 # allow installing when the main user is root
-ENV npm_config_unsafe_perm true
+ENV npm_config_unsafe_perm=true
 # disable NPM funding messages
-ENV npm_config_fund false
+ENV npm_config_fund=false
 
 # Set locale to en_US.UTF-8
 RUN echo "LC_ALL=en_US.UTF-8" >> /etc/environment && \
@@ -119,7 +122,7 @@ RUN echo "LC_ALL=en_US.UTF-8" >> /etc/environment && \
     dpkg-reconfigure locales && \
     locale-gen en_US.UTF-8 && \
     update-locale LC_ALL en_US.UTF-8
-ENV LC_ALL en_US.UTF-8
+ENV LC_ALL=en_US.UTF-8
 
 # Install idnits
 ADD https://raw.githubusercontent.com/ietf-tools/idnits-mirror/main/idnits /usr/local/bin/
diff --git a/docker/scripts/app-setup-debian.sh b/docker/scripts/app-setup-debian.sh
index ddfc351995..ea9cc3fb87 100644
--- a/docker/scripts/app-setup-debian.sh
+++ b/docker/scripts/app-setup-debian.sh
@@ -10,7 +10,6 @@
 # Syntax: ./common-debian.sh [install zsh flag] [username] [user UID] [user GID] [upgrade packages flag] [install Oh My Zsh! flag] [Add non-free packages]
 
 set -e
-
 INSTALL_ZSH=${1:-"true"}
 USERNAME=${2:-"automatic"}
 USER_UID=${3:-"automatic"}
@@ -116,18 +115,9 @@ if [ "${PACKAGES_ALREADY_INSTALLED}" != "true" ]; then
     # Needed for adding manpages-posix and manpages-posix-dev which are non-free packages in Debian
     if [ "${ADD_NON_FREE_PACKAGES}" = "true" ]; then
         # Bring in variables from /etc/os-release like VERSION_CODENAME
-        . /etc/os-release
-        sed -i -E "s/deb http:\/\/(deb|httpredir)\.debian\.org\/debian ${VERSION_CODENAME} main/deb http:\/\/\1\.debian\.org\/debian ${VERSION_CODENAME} main contrib non-free/" /etc/apt/sources.list
-        sed -i -E "s/deb-src http:\/\/(deb|httredir)\.debian\.org\/debian ${VERSION_CODENAME} main/deb http:\/\/\1\.debian\.org\/debian ${VERSION_CODENAME} main contrib non-free/" /etc/apt/sources.list
-        sed -i -E "s/deb http:\/\/(deb|httpredir)\.debian\.org\/debian ${VERSION_CODENAME}-updates main/deb http:\/\/\1\.debian\.org\/debian ${VERSION_CODENAME}-updates main contrib non-free/" /etc/apt/sources.list
-        sed -i -E "s/deb-src http:\/\/(deb|httpredir)\.debian\.org\/debian ${VERSION_CODENAME}-updates main/deb http:\/\/\1\.debian\.org\/debian ${VERSION_CODENAME}-updates main contrib non-free/" /etc/apt/sources.list
-        sed -i "s/deb http:\/\/security\.debian\.org\/debian-security ${VERSION_CODENAME}\/updates main/deb http:\/\/security\.debian\.org\/debian-security ${VERSION_CODENAME}\/updates main contrib non-free/" /etc/apt/sources.list
-        sed -i "s/deb-src http:\/\/security\.debian\.org\/debian-security ${VERSION_CODENAME}\/updates main/deb http:\/\/security\.debian\.org\/debian-security ${VERSION_CODENAME}\/updates main contrib non-free/" /etc/apt/sources.list
-        sed -i "s/deb http:\/\/deb\.debian\.org\/debian ${VERSION_CODENAME}-backports main/deb http:\/\/deb\.debian\.org\/debian ${VERSION_CODENAME}-backports main contrib non-free/" /etc/apt/sources.list 
-        sed -i "s/deb-src http:\/\/deb\.debian\.org\/debian ${VERSION_CODENAME}-backports main/deb http:\/\/deb\.debian\.org\/debian ${VERSION_CODENAME}-backports main contrib non-free/" /etc/apt/sources.list
-        # Handle bullseye location for security https://www.debian.org/releases/bullseye/amd64/release-notes/ch-information.en.html
-        sed -i "s/deb http:\/\/security\.debian\.org\/debian-security ${VERSION_CODENAME}-security main/deb http:\/\/security\.debian\.org\/debian-security ${VERSION_CODENAME}-security main contrib non-free/" /etc/apt/sources.list
-        sed -i "s/deb-src http:\/\/security\.debian\.org\/debian-security ${VERSION_CODENAME}-security main/deb http:\/\/security\.debian\.org\/debian-security ${VERSION_CODENAME}-security main contrib non-free/" /etc/apt/sources.list
+        .  /etc/os-release
+        sed -i -E "s/Components: main/Components: main contrib non-free/" /etc/apt/sources.list.d/debian.sources
+
         echo "Running apt-get update..."
         apt-get update
         package_list="${package_list} manpages-posix manpages-posix-dev"
diff --git a/ietf/submit/tests.py b/ietf/submit/tests.py
index 9a993480cd..6b1c998e76 100644
--- a/ietf/submit/tests.py
+++ b/ietf/submit/tests.py
@@ -1888,7 +1888,7 @@ def test_submit_invalid_yang(self):
         r = self.client.get(status_url)
         q = PyQuery(r.content)
         #
-        self.assertContains(r, 'The yang validation returned 1 error')
+        self.assertContains(r, 'The yang validation returned 3 errors')
         #
         m = q('#yang-validation-message').text()
         for command in ['xym', 'pyang', 'yanglint']:
@@ -1898,7 +1898,7 @@ def test_submit_invalid_yang(self):
         self.assertIn("draft-yang-testing-invalid-00.txt", m)
         self.assertIn("error: syntax error: illegal keyword: ;", m)
         if settings.SUBMIT_YANGLINT_COMMAND and os.path.exists(settings.YANGLINT_BINARY):
-            self.assertIn("No validation errors", m)
+            self.assertIn('libyang err : Parsing module "ietf-yang-metadata" failed.', m)
 
     def submit_conflicting_submissiondocevent_rev(self, new_rev='01', existing_rev='01'):
         """Test submitting a rev when an equal or later SubmissionDocEvent rev exists