diff --git a/.forgejo/workflows/doc.yaml b/.forgejo/workflows/doc.yaml
index a1c0c29..0b12945 100644
--- a/.forgejo/workflows/doc.yaml
+++ b/.forgejo/workflows/doc.yaml
@@ -3,7 +3,7 @@ jobs:
   build-doc:
     runs-on: docker
     container:
-      image: git.tkolb.de/amateurfunk/hamnet70/asciidoctor:1.5
+      image: git.tkolb.de/amateurfunk/hamnet70/asciidoctor:1.6
     steps:
       - uses: actions/checkout@v4
       - run: pwd && ls -hla && cd doc && make
@@ -15,7 +15,7 @@ jobs:
     needs: build-doc
     runs-on: docker
     container:
-      image: git.tkolb.de/amateurfunk/hamnet70/asciidoctor:1.5
+      image: git.tkolb.de/amateurfunk/hamnet70/asciidoctor:1.6
     steps:
       - run: mkdir ~/.ssh && echo "${{ secrets.SSH_KEY }}" > ~/.ssh/id_ed25519 && chmod 0600 ~/.ssh/id_ed25519 && echo "${{ secrets.SSH_KNOWN_HOST }}" > ~/.ssh/known_hosts
       - uses: actions/download-artifact@v3
diff --git a/doc/docker/Dockerfile b/doc/docker/Dockerfile
index 0bd57ea..60a0d7c 100644
--- a/doc/docker/Dockerfile
+++ b/doc/docker/Dockerfile
@@ -9,7 +9,7 @@ RUN gem install asciidoctor asciidoctor-diagram
 RUN apt install -y --no-install-recommends mscgen && apt clean
 
 # tools for automatic deployment
-RUN apt install -y --no-install-recommends rsync && apt clean
+RUN apt install -y --no-install-recommends rsync openssh-client && apt clean
 
 # run as unprivileged user in the container
 RUN useradd -m ciuser