diff --git a/docker/test/style/Dockerfile b/docker/test/style/Dockerfile
index de2c1c64938..a4feae27c67 100644
--- a/docker/test/style/Dockerfile
+++ b/docker/test/style/Dockerfile
@@ -19,7 +19,7 @@ RUN apt-get update && env DEBIAN_FRONTEND=noninteractive apt-get install --yes \
     shellcheck \
     yamllint \
     locales \
-    && pip3 install black==23.1.0 boto3 codespell==2.2.1 mypy==1.3.0 PyGithub pylint==2.6.2 \
+    && pip3 install black==23.1.0 boto3 codespell==2.2.1 mypy==1.3.0 PyGithub unidiff pylint==2.6.2 \
     && apt-get clean \
     && rm -rf /root/.cache/pip 
 
diff --git a/tests/ci/worker/prepare-ci-ami.sh b/tests/ci/worker/prepare-ci-ami.sh
index dc180207be3..f3e11b6d00a 100644
--- a/tests/ci/worker/prepare-ci-ami.sh
+++ b/tests/ci/worker/prepare-ci-ami.sh
@@ -9,7 +9,7 @@ set -xeuo pipefail
 
 echo "Running prepare script"
 export DEBIAN_FRONTEND=noninteractive
-export RUNNER_VERSION=2.310.1
+export RUNNER_VERSION=2.304.0
 export RUNNER_HOME=/home/ubuntu/actions-runner
 
 deb_arch() {
@@ -90,7 +90,8 @@ systemctl restart docker
 sudo -u ubuntu docker buildx version
 sudo -u ubuntu docker buildx create --use --name default-builder
 
-pip install boto3 pygithub requests urllib3 dohq-artifactory
+# FIXME: remove unidiff as soon as no old PRs could use it, here and in Dockerfile
+pip install boto3 pygithub requests urllib3 unidiff dohq-artifactory
 
 mkdir -p $RUNNER_HOME && cd $RUNNER_HOME