Sure, but in spirit I would put the same information in both. Apple's rules on that field are just strange–when a new version of iOS goes into GM out you cannot mention it in your release notes (added support for iOS 14!), which really just makes no sense. It's presented as a place to put your update notes except it's really a strange field where you put something that is similar to your update notes but edited to comply with unwritten guidelines that Apple has created that you can only really know if you read Twitter and see what kinds of things Apple will let you put there.