diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 4fb0b0e..e759779 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,170 +1,171 @@
 stages:
   - docker
   - build
   - test
   - deploy
 
 variables:
   IMAGE_TAG: $CI_REGISTRY_IMAGE:$CI_COMMIT_REF_SLUG
   GIT_SUBMODULE_STRATEGY: recursive
   BUILD_DIR: build-release
 
 cache:
   key: "$CI_COMMIT_REF_SLUG"
 
 # ------------------------------------------------------------------------------
 
 .docker_build:
   stage: docker
   image: docker:19.03.12
   services:
     - docker:19.03.12-dind
   variables:
     # Use TLS https://docs.gitlab.com/ee/ci/docker/using_docker_build.html#tls-enabled
     DOCKER_HOST: tcp://docker:2376
     DOCKER_TLS_CERTDIR: "/certs"
+    DEFAULT_IMAGE: $CI_REGISTRY_IMAGE:$CI_DEFAULT_BRANCH
   before_script:
     - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
   script:
-    - docker pull $IMAGE_TAG-$IMAGE_NAME || true
-    - docker build --cache-from $IMAGE_TAG-$IMAGE_NAME
+    - docker pull $DEFAULT_IMAGE-$IMAGE_NAME || true
+    - docker build --cache-from $DEFAULT_IMAGE-$IMAGE_NAME
                    -t $IMAGE_TAG-$IMAGE_NAME -f $DOCKERFILE .
     - docker push $IMAGE_TAG-$IMAGE_NAME
 
 docker build:debian:
   variables:
     IMAGE_NAME: debian-stable
     DOCKERFILE: tests/ci/docker/debian.mpi
   extends: .docker_build
 
 docker build:manylinux:
   variables:
     IMAGE_NAME: manylinux
     DOCKERFILE: tests/ci/docker/manylinux
   extends: .docker_build
 
 docker build:cuda:
   variables:
     IMAGE_NAME: cuda
     DOCKERFILE: tests/ci/docker/ubuntu_lts.cuda
   extends: .docker_build
 
 # ------------------------------------------------------------------------------
 
 .debian_stable:
   image: $IMAGE_TAG-debian-stable
 
 .manylinux:
   image: $IMAGE_TAG-manylinux
 
 .cuda:
   image: $IMAGE_TAG-cuda
 
 # ------------------------------------------------------------------------------
 
 .build:
   stage: build
   variables:
     COMPILE_LOG: compilation.log
   script:
     - scons 2>&1 | tee $COMPILE_LOG
   artifacts:
     paths:
       - build-setup.conf
       - $COMPILE_LOG
       - $BUILD_DIR
       - config.log
 
 build:mpi:
   extends:
     - .build
     - .debian_stable
   before_script:
     - scons build_tests=True
             use_googletest=True
             build_python=True
             py_exec=python3
             use_mpi=True
             backend=omp
             fftw_threads=omp
             verbose=True -h
 
 build:cuda:
   extends:
     - .build
     - .cuda
   before_script:
     - scons build_tests=True
             use_googletest=True
             build_python=True
             py_exec=python3
             use_mpi=False
             backend=cuda
             fftw_threads=none
             verbose=True -h
 
 # ------------------------------------------------------------------------------
 
 test:mpi:
   stage: test
   dependencies:
     - build:mpi
   extends: .debian_stable
   variables:
     PYTHONPATH: $CI_PROJECT_DIR/$BUILD_DIR/python
     TESTS: $BUILD_DIR/tests
     JUNITXML: results.xml
     TESTS_LOG: tests.log
   script:
     - ls $PYTHONPATH
     - python3 -c 'import sys; print(sys.path)'
     - python3 -m pytest -vvv --durations=0 --junitxml=$JUNITXML
       $TESTS 2>&1 | tee $TESTS_LOG
   artifacts:
     paths:
       - $JUNITXML
       - $TESTS_LOG
     reports:
       junit:
         - $JUNITXML
 
 # ------------------------------------------------------------------------------
 
 .protected_refs:
   extends: .manylinux
   rules:
     - if: '$CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH || $CI_COMMIT_TAG =~ /^v.*/'
 
 wheels:
   stage: build
   extends: .protected_refs
   script:
     - ./tests/ci/build_wheels.sh
   artifacts:
     paths:
       - dist/wheelhouse
 
 # ------------------------------------------------------------------------------
 
 .deploy_wheels:
   stage: deploy
   extends: .protected_refs
   dependencies:
     - wheels
   script:
     python -m twine upload --verbose dist/wheelhouse/*
 
 package:gitlab:
   extends: .deploy_wheels
   variables:
     TWINE_USERNAME: gitlab-ci-token
     TWINE_PASSWORD: ${CI_JOB_TOKEN}
     TWINE_REPOSITORY_URL: ${CI_API_V4_URL}/projects/${CI_PROJECT_ID}/packages/pypi
 
 package:pypi:
   extends: .deploy_wheels
   variables:
     TWINE_USERNAME: __token__
     TWINE_PASSWORD: ${PYPI_TOKEN}
   rules:
     - if: '$CI_COMMIT_TAG =~ /^v.*/'