diff --git a/sdk/SDK.csproj b/sdk/SDK.csproj
index c81b639..be3351a 100644
--- a/sdk/SDK.csproj
+++ b/sdk/SDK.csproj
@@ -13,7 +13,7 @@
     <RepositoryUrl>https://github.com/tokenio/sdk-csharp</RepositoryUrl>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="Google.Protobuf" Version="3.7.0" />
+    <PackageReference Include="Google.Protobuf" Version="3.15.0" />
     <PackageReference Include="Grpc" Version="1.20.1" />
     <PackageReference Include="Grpc.Core" Version="1.20.1" />
     <PackageReference Include="log4net" Version="2.0.8" />