diff --git a/1-DotNet30/demos/grpc/grpc-sample/GrpcClient.Lib/GrpcClient.Lib.csproj b/1-DotNet30/demos/grpc/grpc-sample/GrpcClient.Lib/GrpcClient.Lib.csproj
index 1623ec0..082b3ca 100644
--- a/1-DotNet30/demos/grpc/grpc-sample/GrpcClient.Lib/GrpcClient.Lib.csproj
+++ b/1-DotNet30/demos/grpc/grpc-sample/GrpcClient.Lib/GrpcClient.Lib.csproj
@@ -9,7 +9,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Google.Protobuf" Version="3.10.0" />
+    <PackageReference Include="Google.Protobuf" Version="3.15.0" />
     <PackageReference Include="Grpc.Net.Client" Version="2.23.2" />
     <PackageReference Include="Grpc.Tools" Version="2.24.0">
       <PrivateAssets>all</PrivateAssets>