What version of ProtoBuf does protobuf-net use?

“Version” can mean many things:

The Binary Protocol

The binary ProtoBuf protocol has not changed at all in the time in which it has been available open-source; protobuf-net provides an implementation of the binary protocol, and as such it is not currently directly meaningful to ask what version of the binary protocol is supported: there is only one version, and it is supported.

The Schema Processing Tools

Back a few years ago, protobuf-net’s schema-processing tools (which are entirely optional, to support users with .proto files) made use of protoc. However, the tools have now been re-written using entirely managed code, and as such have no dependency on protoc at all, and therefore have no versioning relevance to protoc.

The .proto Syntax

The .proto schema language currently has 2 major versions; "proto2" and "proto3"; protogen fully supports both syntax versions and has been tested against a wide corpus of available schemas. The generated code includes all conventions known up to 3.5.1 (the current version at time of writing), and some not-yet-released post-3.5.1 changes such as the re-addition of unknown field support for "proto3" messages.

The Library/Runtime

protobuf-net does not make use of any part of the Google codebase (except for example .proto files, for testing purposes), and so is not tied in any way to ProtoBuf library versions.

Other Features

There are, however, some ProtoBuf features that protobuf-net does not support; for example: