We currently have three active release branches: 3.0, 2.6, and 2.4. This is because we support each release branch for a set amount of time (typically 24 months after the initial .0 release) and our last three .0 releases were less than 12 months apart. However, having many active branches can sometimes cause confusion[1] and far fewer people download the "Old Old Stable" release than the "Old Stable" or "Stable" releases. Would it make sense to have only two release branches active at any given time, e.g. by adjusting our release branch lifetimes to "24 months or whenever we have two newer active branches, whichever comes first"?
We've also been using odd minor numbers for development releases and even minor numbers for stable releases[2] for many years now. We don't make very many development releases and instead tend to have one or more release candidates after branch is created. Would it make sense to drop the even/odd scheme and make the next major release 3.1.0?
As others have said, that should be OK as long as the version in the not-released-yet code is identifiable. IIRC part of what got us into odd/even was:
(Basically: the master branch's version was 0.99.7 while that version was in development.
sunfreeware.com couldn't get the prior release to build so they built from SVN and released the software that called itself 0.99.7 - before we released it.)