diff --git a/.github/workflows/build-ilspy.yml b/.github/workflows/build-ilspy.yml
index 136ff73b4..8357f0f38 100644
--- a/.github/workflows/build-ilspy.yml
+++ b/.github/workflows/build-ilspy.yml
@@ -42,7 +42,7 @@ jobs:
     - name: Setup .NET Core
       uses: actions/setup-dotnet@v1
       with:
-        dotnet-version: '5.0.x'
+        dotnet-version: '3.1.x'
 
     - name: Add msbuild to PATH
       uses: microsoft/setup-msbuild@v1.0.2