In addition, the dictionary table migrations have been neutered, and there won't be one for new installations (see
https://github.com/geek1011/kobopatc...ment-596238620). This means that
it is not safe to downgrade from a fresh installation (upgrades are fine) of 4.20.14601 while preserving the database as-is (you need to factory reset to an older version or recreate the dictionary table first).
I suspect that the reason the migrations were changed rather than adding a new one is so they didn't have to keep the old dictionary db manipulation cruft (which the migrations depend on) around.