How big are the changes between 4.2.2 and 4.3?
So, I finally got back to this, sorry for the late reply. After reading through kombu 4.3 changelog [0], it seems the only truly breaking change is in SQLAlchemy transport ( I can be wrong, of course) which would require manual intervention in the database:
"Added an index to the Message table for the SQLAlchemy transport."
From what I understand, using SQLAlchemy for celery/kombu is pretty niche and documentation mentions and most applications around the world I was able to find are using different backends for celery (RabbitMQ, Redis).
The plan will be to leave the upgraded stack for a long time in testing, I was thinking about something like a month or two. I'll definitely send an announcement once the stack is in testing repo and then (week or two) before pushing it to epel stable.