diff --git a/IOST.Rpcpb.Net45/packages.config b/IOST.Rpcpb.Net45/packages.config
index 781cd65..cb4d7cf 100644
--- a/IOST.Rpcpb.Net45/packages.config
+++ b/IOST.Rpcpb.Net45/packages.config
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
-  <package id="Google.Protobuf" version="3.8.0" targetFramework="net45" />
+  <package id="Google.Protobuf" version="3.15.0" targetFramework="net45" />
   <package id="Grpc.Core" version="1.22.0" targetFramework="net45" />
   <package id="Grpc.Core.Api" version="1.22.0" targetFramework="net45" />
   <package id="Grpc.Tools" version="1.22.0" targetFramework="net45" developmentDependency="true" />