For the record, IIRC we "broke" backwards compat twice. Both times it was to fix incorrect behavior which caused more issues broken then it would fixed.

Stability is very important to the Moose community because many of us have applications running in prod which our jobs/livelihoods depend on. Any change made is made with lots of consideration and only if we feel the pros outweigh the cons.

If we ever were to add auto-magic usage of 5.10 features in Moose, it would be 100% completely optional. Moose proudly runs on 5.6 and up.