diff --git a/src/TensorFlowNET.Core/TensorFlowNET.Core.csproj b/src/TensorFlowNET.Core/TensorFlowNET.Core.csproj
index 007eccc8..3037221c 100644
--- a/src/TensorFlowNET.Core/TensorFlowNET.Core.csproj
+++ b/src/TensorFlowNET.Core/TensorFlowNET.Core.csproj
@@ -68,7 +68,7 @@ Docs: https://tensorflownet.readthedocs.io</Description>
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Google.Protobuf" Version="3.9.0" />
+    <PackageReference Include="Google.Protobuf" Version="3.5.1" />
     <PackageReference Include="NumSharp" Version="0.10.6" />
   </ItemGroup>