We have two schema variants for now, one is a legacy schema which we want
to retire eventually but it is still used by many installations. Newer
variant provides new features, and installations that require those new
features have to migrate immediately. OTOH we do not want to require
everyone
I'm quite curious about why you need to maintain all these different
versions of the same database. Like in code, you branch out to be able to
do development in parallel without interfering other development, and
eventually you merge back. But here it seems you want to keep multiplying
the number
