diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index b8d284532bd7afa780cd988dc9357697238de3cd..418add2c8e65e2f97902fd94c11628f0f28604cb 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -17,7 +17,7 @@
 # See other available tags for .NET Core: https://hub.docker.com/_/microsoft-dotnet
 # Learn more about Docker tags: https://docs.docker.com/glossary/?term=tag
 # and the Docker itself: https://opensource.com/resources/what-docker
-image: mcr.microsoft.com/dotnet/sdk:latest
+image: mcr.microsoft.com/dotnet/sdk:3.1
 
 # ### Define variables
 #