As for the identifier
the documentation says:
A unique identifier for the request (if identifier is not unique, notifications are not delivered). You can use this identifier later to cancel a request that is still pending. This parameter must not be nil.
It's says it's not delivered. However according to here and according to my own verification it does get delivered, but it rewrites the previous notification sent with that identifier.
So I'm guessing the apple documentation should have said:
if identifier is same, it will only update the previous sent notification. If you want a separate notification, you must change its identifier.
Am I right about the documentation being wrote in a confusing way?