diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -8,7 +8,7 @@
   script:
     - csi scripts/LoadYaml.csx
     - csi scripts/LoadInk.csx
-  image: mcr.microsoft.com/dotnet/sdk:5.0-focal
+  image: mcr.microsoft.com/dotnet/runtime:3.1-focal
 
 build-debug:
   stage: build