diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index a210b77..6c0e614 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -16,7 +16,7 @@ jobs:
     - name: Setup .NET  
       uses: actions/setup-dotnet@v1  
       with:  
-        dotnet-version: '7.0'  # update this to your .NET version  
+        dotnet-version: '5.0'  # update this to your .NET version  
   
     - name: Build  
       run: dotnet build DdfGuide.Core/DdfGuide.Core.csproj