Version 5 is still evolving and new stuff is added in every release, in fact we’ve already released 5.2.0!. However, as we iterate on v5, we also fix bugs that have existed for a few versions and are still present in the latest v4 release. So, time to time, we’ll try to backport some fix from the v5 into the v4. We’ll try to do it every week or two, it will depend on how many fixes we release in the v5.
This week we released 4.12.6.
Since we can’t really know how many people are still using a v4 of MediumEditor, we don’t know how long we’ll keep doing that.
Anyway, the migration from v4 to v5 isn’t that hard to do. If you didn’t use custom extensions or haven’t hacked too much into the core, the update should be easy. You just need to follow the upgrade file, which contains all breaking changes in detail.