While we strive to limit the changes to the database as much as possible for any type of release, what you are asking is to change our complete versioning schema, which is not something we would do overnight.
To clarify: we’ve had the 7.x line for a long time now, and as you can read in Flowable 7.2.0 release we’re now working on a 8.x, mainly because the upcoming Spring/Jackson changes. So this is really a discussion about version numbers, i.e. for us a 7.x.a → 7.x.b is a minor change, while changing the x is a major one. Changing the 7 to 8 means a major change, e.g. a new engine architecture (the 5 –> 6 for example), or changes that have a huge impact potentially (e.g. the 7 –> 8).