Hook changes
Filter
filter:user.custom_fields removed see this commit
filter:user.delete deprecated, use static:user.delete instead, now
It is passed { uid: uid } instead of just uid, and is fired before user data is actually deleted, so you have one last chance to look up stuff if needed.
Other changes
Theme developers should now explicitly set the baseTheme in their theme.json if their theme is not based on Persona. Set this value to nodebb-theme-vanilla
TBD