The Rack web API already does that for the major version. So if a plugin exists for both API version 1.x and 2.x, and you call the update from Rack 2.x you’ll get the 2.x version. It would seem that might be necessary now as well for the minor version.
Yes, for some value of “breaking”.
From this:
VCV’s take on this is that all users should just update to Rack 2.3 as it is the latest version and its free to do so.