diff --git a/docker/domserver/Dockerfile b/docker/domserver/Dockerfile
index 8248cde6..400079d2 100644
--- a/docker/domserver/Dockerfile
+++ b/docker/domserver/Dockerfile
@@ -1,4 +1,4 @@
-FROM debian:bullseye-slim AS domserver-build
+FROM debian:bookworm-slim AS domserver-build
 LABEL org.opencontainers.image.authors="DOMjudge team <team@domjudge.org>"
 
 ENV DEBIAN_FRONTEND=noninteractive
@@ -12,13 +12,16 @@ RUN apt update \
 	php-gd php-curl php-mysql php-json php-intl \
 	php-gmp php-xml php-mbstring \
 	sudo bsdmainutils ntp libcgroup-dev procps \
-	python3-sphinx python3-sphinx-rtd-theme python3-pygments rst2pdf fontconfig python3-yaml \
+	python3-venv fontconfig \
 	texlive-latex-recommended texlive-latex-extra \
-	texlive-fonts-recommended texlive-lang-european latexmk \
+	texlive-fonts-recommended texlive-lang-european latexmk tex-gyre \
 	libcurl4-gnutls-dev libjsoncpp-dev libmagic-dev \
 	enscript lpr ca-certificates \
 	&& rm -rf /var/lib/apt/lists/*
 
+# Use venv to install latest Sphinx. 6.1.0 or higher is required to build DOMjudge docs.
+RUN python3 -m venv /venv && . /venv/bin/activate && pip3 install sphinx sphinx-rtd-theme rst2pdf
+
 # Set up user
 RUN useradd -m domjudge
 
@@ -40,7 +43,7 @@ RUN chmod 700 /scripts/patches.sh && /scripts/patches.sh
 RUN /domjudge-src/build.sh
 
 # Now create an image with the actual build in it
-FROM debian:bullseye-slim
+FROM debian:bookworm-slim
 LABEL org.opencontainers.image.authors="DOMjudge team <team@domjudge.org>"
 
 ENV DEBIAN_FRONTEND=noninteractive \
diff --git a/docker/domserver/build.sh b/docker/domserver/build.sh
index cf660477..4ab23958 100755
--- a/docker/domserver/build.sh
+++ b/docker/domserver/build.sh
@@ -1,9 +1,12 @@
 #!/bin/sh -eu
 
+# Use venv to use latest Sphinx. 6.1.0 or higher is required to build DOMjudge docs.
+. /venv/bin/activate
+
 cd /domjudge-src/domjudge*
 chown -R domjudge: .
 # If we used a local source tarball, it might not have been built yet
-sudo -u domjudge make dist
+sudo -u domjudge sh -c '. /venv/bin/activate && make dist'
 sudo -u domjudge ./configure -with-baseurl=http://dj.chipcie.ch.tudelft.nl/
 
 # Passwords should not be included in the built image. We create empty files here to prevent passwords from being generated.
@@ -25,5 +28,5 @@ then
 	rm /opt/domjudge/domserver/webapp/.env.local /opt/domjudge/domserver/webapp/.env.local.php
 fi
 
-sudo -u domjudge make docs
+sudo -u domjudge sh -c '. /venv/bin/activate && make docs'
 make install-docs
diff --git a/docker/domserver/configure.sh b/docker/domserver/configure.sh
index 55684046..5bd82143 100644
--- a/docker/domserver/configure.sh
+++ b/docker/domserver/configure.sh
@@ -23,7 +23,7 @@ done
 
 # Configure php
 
-php_folder=$(echo "/etc/php/7."?"/")
+php_folder=$(echo "/etc/php/8."?"/")
 php_version=$(basename "$php_folder")
 
 if [ ! -d "$php_folder" ]