diff --git a/.circleci/config.yaml b/.circleci/config.yml
similarity index 96%
rename from .circleci/config.yaml
rename to .circleci/config.yml
index 6b00ab7..4715422 100644
--- a/.circleci/config.yaml
+++ b/.circleci/config.yml
@@ -9,7 +9,7 @@ jobs:
     # You can specify an image from Dockerhub or use one of our Convenience Images from CircleCI's Developer Hub.
     # Be sure to update the tag on this image to a more stable version, using latest can result in unstable builds.
     docker:
-      - image: microsoft/dotnet:latest
+      - image: mcr.microsoft.com/dotnet/sdk:3.1
     steps:
       # Checkout the code as the first step.
       - checkout