diff --git a/.docker/Dockerfile b/.docker/Dockerfile
index 67cd4a32fb117a3aac3bfbba2a28fbc375e1f10a..2763c0548263a8595629de0ced2f23e761d397e1 100644
--- a/.docker/Dockerfile
+++ b/.docker/Dockerfile
@@ -35,4 +35,5 @@ RUN rm -r /git/.git \
 RUN cd /git && pip3 install .
 WORKDIR /git/integrationtests
 CMD /wait-for-it.sh caosdb-server:10443 -t 500 -- ./test.sh
+# At least recommonmark 0.6 required.
 RUN pip3 install recommonmark
diff --git a/README_SETUP.md b/README_SETUP.md
index 4f3a6998b676e04bc5729b54aa2a27103a1850cf..7d4cce6ec1fb09d8f52e31f67581eb74127fc87a 100644
--- a/README_SETUP.md
+++ b/README_SETUP.md
@@ -38,4 +38,4 @@ Build documentation in `build/` with `make doc`.
 
 - sphinx
 - sphinx-autoapi
-- recommonmark
+- recommonmark >= 0.6.0