diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index aa1622a4e376096abf23f053c38af2558e0f57e7..d37bd15d9d57535a688729e579f57668574306c9 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -82,10 +82,12 @@ tests-3.9:
   image: docker:latest
   services:
     - docker:dind
+  variables:
+    PYTHON_VERSION: "3.9"
   script:
     - docker login -u "$CI_REGISTRY_USER" -p "$CI_BUILD_TOKEN" $CI_REGISTRY
     - docker pull $CI_REGISTRY_IMAGE/$KIND:$CI_COMMIT_SHORT_SHA || true
-    - docker build --cache-from $CI_REGISTRY_IMAGE/$KIND:$CI_COMMIT_SHORT_SHA --pull -t "$CI_REGISTRY_IMAGE/$KIND:$CI_COMMIT_SHORT_SHA" -f release/$KIND-image .
+    - docker build --cache-from $CI_REGISTRY_IMAGE/$KIND:$CI_COMMIT_SHORT_SHA --pull -t "$CI_REGISTRY_IMAGE/$KIND:$CI_COMMIT_SHORT_SHA" -f release/$KIND-image --build-arg PYTHON_VERS=$PYTHON_VERSION .
     - docker push "$CI_REGISTRY_IMAGE/$KIND:$CI_COMMIT_SHORT_SHA"
     - docker tag "$CI_REGISTRY_IMAGE/$KIND:$CI_COMMIT_SHORT_SHA" "$CI_REGISTRY_IMAGE/$KIND:$CI_COMMIT_BRANCH"
     - docker push "$CI_REGISTRY_IMAGE/$KIND:$CI_COMMIT_BRANCH"
diff --git a/release/pip-image b/release/pip-image
index dccbe25395e477ca96772f3a2c9e6498a532f879..d4466bcde2b0db0c93d59736152c2d89a2c43cf5 100644
--- a/release/pip-image
+++ b/release/pip-image
@@ -1,7 +1,7 @@
 # ------------------------------------------------------------------------------
 # Build Stage
 # ------------------------------------------------------------------------------
-ARG PYTHON_VERS=3.9
+ARG PYTHON_VERS
 FROM python:${PYTHON_VERS}-slim-buster AS build
 
 WORKDIR /silkaj
@@ -16,7 +16,7 @@ RUN pip install .
 # Final Stage
 # ------------------------------------------------------------------------------
 FROM python:${PYTHON_VERS}-slim-buster
-ARG PYTHON_VERS=3.9
+ARG PYTHON_VERS
 
 # Create silkaj group and user
 RUN groupadd -g 1111 silkaj && \
diff --git a/release/poetry-image b/release/poetry-image
index 08ba73bbbf03d7c6ab35d402d726ebc82ec1277b..0fd4f8fbf2c6322c04ccf93e7d6f2dd7e7451c1a 100644
--- a/release/poetry-image
+++ b/release/poetry-image
@@ -1,7 +1,7 @@
 # ------------------------------------------------------------------------------
 # Build Stage
 # ------------------------------------------------------------------------------
-ARG PYTHON_VERS=3.9
+ARG PYTHON_VERS
 FROM registry.duniter.org/docker/python3/poetry/${PYTHON_VERS}:latest AS build
 
 WORKDIR /silkaj
@@ -16,7 +16,7 @@ RUN poetry install --no-dev
 # Final Stage
 # ------------------------------------------------------------------------------
 FROM registry.duniter.org/docker/python3/poetry/${PYTHON_VERS}:latest
-ARG PYTHON_VERS=3.9
+ARG PYTHON_VERS
 
 # Create silkaj group and user
 RUN groupadd -g 1111 silkaj && \