diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 9328bd1c5e1ea0e7ba5044c719508040774441bd..8f9f0c95671e04d76c2ddcbc172a5fc5f2e1b216 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -54,9 +54,7 @@ check-copyrights:
 
 ##########################################################
 check-clang-format:
-  image: corsika/devel:u-18.04
-  before_script:
-  - apt-get update && apt-get install -y -qq clang-format
+  image: corsika/devel:clang-8
   stage: quality
   tags:
     - corsika
diff --git a/do-clang-format.py b/do-clang-format.py
index 3b760eadb0d7923584d0df41462aabb2f39bdc5f..b2a2020648a5634c882cdbe3c16494bdb993b31e 100755
--- a/do-clang-format.py
+++ b/do-clang-format.py
@@ -49,7 +49,10 @@ else:
     filelist = [x for x in filelist
                 if "ThirdParty" not in x and (x.endswith(".h") or x.endswith(".cc"))]
 
-cmd = "clang-format -style=file"
+cmd = "clang-format"
+if "CLANG_FORMAT" in os.environ:
+  cmd = os.environ["CLANG_FORMAT"]
+cmd +=  " -style=file"
 if args.apply:
     for filename in filelist:
         subp.check_call(cmd.split() + ["-i", filename])