diff --git a/serving/grpc/csharp/GrpcGreeterClient/GrpcGreeterClient.csproj b/serving/grpc/csharp/GrpcGreeterClient/GrpcGreeterClient.csproj
index 7f64998..dec1125 100644
--- a/serving/grpc/csharp/GrpcGreeterClient/GrpcGreeterClient.csproj
+++ b/serving/grpc/csharp/GrpcGreeterClient/GrpcGreeterClient.csproj
@@ -10,7 +10,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Google.Protobuf" Version="3.9.0" />
+    <PackageReference Include="Google.Protobuf" Version="3.15.0" />
     <PackageReference Include="Grpc.Net.Client" Version="0.1.22-pre2" />
     <PackageReference Include="Grpc.Tools" Version="1.22.0">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>