tor-spec.txt says it only applies to tor 0.2.1.x
tor-spec.txt starts with
Note: This document aims to specify Tor as implemented in 0.2.1.x. Future
versions of Tor may implement improved protocols, and compatibility is not
guaranteed.
I think tor-spec captures 0.2.2.x and 0.2.3.x as well as this point.
Should we just name those two branches too? If so, we're going to forget to add 0.2.4 when the time comes. We should think of a more future-proofy approach.