proto2 and proto3 should be wire-compatible:
see [https://groups.google.com/forum/#!topic/protobuf/wAqvtPLBsE8](https://groups.google.com/forum/#!topic/protobuf/wAqvtPLBsE8)
- Protobuf v2 support whospal
- Re: Protobuf v2 support daef
proto2 and proto3 should be wire-compatible:
see [https://groups.google.com/forum/#!topic/protobuf/wAqvtPLBsE8](https://groups.google.com/forum/#!topic/protobuf/wAqvtPLBsE8)