It never happened because (IMO, I'm guessing), no-one actually needs nanomsg. I've never really understood the hostility some people had towards e.g. the ZeroMQ protocols, since these RFCs are as plastic and open to contributions as any part of the project. Yet people like to react against things, and this was a large part of nano's reason for existence. In reality, people who need stable working code just take ZeroMQ and that's it.

Which is all kind of a shame since it would have been so nice to see a new C engine in the community. We have new engines in C#, Erlang, Java, yet the old core project is still that somewhat clunky C++ engine.