Growing major version

Even with incremental numbers, you may run into the issue where you need a major bump rather than a minor. Depending on the maintenance guarantees, this may mean the current major version is "undead".

What we've ended up doing is that the release branch is x.y.z where "z" is "small". But the main development branch pushes "z" way above any actual patch release number by using the integer formed by YYYYMMDD. This is then bumped nightly. So while, say, 5.3.3 is the "latest release", development is at 5.3.20260214. Below any future release, but also way higher than any conceivable incremented patch number. Then if you end up saying "yep, 6.0 is coming" then walking it back to "whoops, the big feature missed the schedule, back to 5.4", you're still monotonic.