diff --git a/server/tools/protobuild/ss_proto.proto b/server/tools/protobuild/ss_proto.proto
index 7a5bdf1..8c1e148 100755
--- a/server/tools/protobuild/ss_proto.proto
+++ b/server/tools/protobuild/ss_proto.proto
@@ -96,6 +96,7 @@ message MFUserDB
     repeated MFFriendDB friends = 1;
     optional MFRole role_data = 2;
     repeated MFFriendDB black_list = 3;
+    optional int64 private_chat_last_id = 4;
 }
 
 message SS_WSP_SocketDisconnect