diff --git a/src/grpc-server/grpc-server.csproj b/src/grpc-server/grpc-server.csproj
index 4718327..9dcfc0a 100644
--- a/src/grpc-server/grpc-server.csproj
+++ b/src/grpc-server/grpc-server.csproj
@@ -6,7 +6,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Google.Protobuf" Version="3.5.1" />
+    <PackageReference Include="Google.Protobuf" Version="3.15.0" />
     <PackageReference Include="Grpc.Core" Version="1.10.0" />
     <PackageReference Include="Grpc.Tools" Version="1.10.0" />
     <PackageReference Include="Microsoft.Extensions.Logging" Version="2.0.1" />
diff --git a/src/grpc-service/grpc-service.csproj b/src/grpc-service/grpc-service.csproj
index d863b65..c773809 100644
--- a/src/grpc-service/grpc-service.csproj
+++ b/src/grpc-service/grpc-service.csproj
@@ -5,7 +5,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Google.Protobuf" Version="3.5.1" />
+    <PackageReference Include="Google.Protobuf" Version="3.15.0" />
      <PackageReference Include="Grpc.Core" Version="1.10.0" />
   </ItemGroup>