diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 50e9a7f8feddde807768764689f7257b325c740e..9cb05d0baa85bf620c7c2c93e3037b5ea8646b14 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -35,7 +35,7 @@ build-env-job:       # This job runs in the build stage, which runs first.
   # docu: https://docs.gitlab.com/ee/ci/docker/using_kaniko.html, this is basically copy-pasted from there
   script:
     - mkdir -p /kaniko/.docker
-    - echo "{\"auths\":{\"$CI_REGISTRY\":{\"auth\":\"$(printf "%s:%s" "$CI_REGISTRY_USER" "$CI_REGISTRY_PASSWORD" | base64 | tr -d '\n')\"},\"$(printf "%s" "$CI_DEPENDENCY_PROXY_SERVER" | cut -d':' -f1)\":{\"auth\":\"$(printf "%s:%s" "$CI_DEPENDENCY_PROXY_USER" "$CI_DEPENDENCY_PROXY_PASSWORD" | base64 | tr -d '\n')\"}}}" > /kaniko/.docker/config.json
+    - echo "{\"auths\":{\"${HARBOR_HOST}\":{\"auth\":\"$(echo -n ${HARBOR_USERNAME}:${HARBOR_PASSWORD} | base64)\"}},\"$(printf "%s" "$CI_DEPENDENCY_PROXY_SERVER" | cut -d':' -f1)\":{\"auth\":\"$(printf "%s:%s" "$CI_DEPENDENCY_PROXY_USER" "$CI_DEPENDENCY_PROXY_PASSWORD" | base64 | tr -d '\n')\"}}}" > /kaniko/.docker/config.json;
     # In this task, Kaniko executor is called to build the Image based on the Dockerfile provided with "--dockerfile".
     - echo "CI_PROJECT_DIR=${CI_PROJECT_DIR}"
     - >-
diff --git a/gitlab-ci/Dockerfile b/gitlab-ci/Dockerfile
index 12896f0c37ea3791fc579343d63f6687fe8d99d6..41d7318be628524d78b10495a2ed3575a46d20a8 100644
--- a/gitlab-ci/Dockerfile
+++ b/gitlab-ci/Dockerfile
@@ -1,4 +1,4 @@
-FROM git.slub-dresden.de/debian-packaging/dependency_proxy/containers/debian:bullseye-slim
+FROM sdvharbor.slub-dresden.de/replication/debian:bookworm-slim
 
 ARG GITDIR
 ENV DEBIAN_FRONTEND=noninteractive
@@ -9,7 +9,7 @@ ENV EXLIBRIS_PATH=/exlibris
 RUN apt-get update; \
     apt-get install -y --no-install-recommends gnupg wget; \
     wget -O - http://sdvdebianrepo.slub-dresden.de/deb-repository/pub.gpg.key | apt-key add - ; \
-    echo "deb http://sdvdebianrepo.slub-dresden.de/deb-repository bullseye main" > /etc/apt/sources.list.d/slub.list;
+    echo "deb http://sdvdebianrepo.slub-dresden.de/deb-repository bookworm main" > /etc/apt/sources.list.d/slub.list;
 
 RUN apt-get update; \
     apt-get -y upgrade; \