I don’t have a favourite new feature, but I’m just learning about the Compound constraint which I’ll definitely put to use in the near future.

I do have a favourite deprecation, of Removing the Default Garbage Collector Probability option. I’ve had weird and spaced out crashes when developing before I knew about this. Apparently this is to remove stale sessions once in a while. According to this comment, Debian based distros already handle it cleanly with a cron job, so I just unset that Symfony setting