diff --git a/.docker/Dockerfile b/.docker/Dockerfile
index 0a7d2f0f2681c79ec57135ae850a6c3063a54635..956a017d18f9e26dc265d3900432ee4995a6bcb5 100644
--- a/.docker/Dockerfile
+++ b/.docker/Dockerfile
@@ -1,5 +1,5 @@
 ARG CPPLIB_REGISTRY_IMAGE
-ARG CPPLIB_VERSION
+ARG CPPLIB_VERSION=bla
 FROM $CPPLIB_REGISTRY_IMAGE
 
 COPY .docker/wait-for-it.sh /wait-for-it.sh
@@ -24,10 +24,10 @@ RUN echo $ENV_CPPLIB_VERSION
 # build and run tests
 CMD ls -la && \
     ls -la /usr/local/lib/ && \
-    ls -la /usr/local/lib/libcaosdb-${ENV_CPPLIB_VERSION} && \
+    ls -la /usr/local/lib/libcaosdb-$ENV_CPPLIB_VERSION && \
     mkdir build && \
     cd build && \
     /wait-for-it.sh caosdb-server:10443 -t 500 -- \
-    cmake -D CMAKE_PREFIX_PATH=/usr/local/lib/libcaosdb-${ENV_CPPLIB_VERSION} .. && \
+    cmake -D CMAKE_PREFIX_PATH=/usr/local/lib/libcaosdb-$ENV_CPPLIB_VERSION .. && \
     cmake --build . && \
     ctest
diff --git a/.docker/run.sh b/.docker/run.sh
index b0e1a716f28516b83043fb3fdb6594515a0bafd4..3853befaae8bc63a8a563042f31252088824766e 100755
--- a/.docker/run.sh
+++ b/.docker/run.sh
@@ -1,5 +1,6 @@
 #!/bin/sh
 
-docker-compose -f tester.yml run tester
+echo $CPPLIB_VERSION
+CPPLIB_VERSION=$CPPLIB_VERSION docker-compose -f tester.yml run tester
 rv=$?
 echo $rv > result
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 8a0ea33c75896948fd25096fe0e9f69cb0c9799c..5c0297e3ca6f177c2f3a22965f317c88f25e5c4d 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -164,7 +164,7 @@ test:
 
       # the pyinttest docker writes the return value of the tests into the
       # file result
-    - /bin/sh ./run.sh
+    - CPPLIB_VERSION=$CPPLIB_VERSION /bin/sh ./run.sh
 
       # collect log files
     - docker logs docker_caosdb-server_1 &> ../caosdb_log.txt