Last week, I upgraded from iOS 12 to iOS 13 on my iPhone XS – all was fine. Due to upgrading to an 11 Pro, I then made an iCloud Backup on my XS, and then restored to the just-created backup on my new 11 Pro – again, all fine.
Since that time, however, I've noticed that I'm not receiving push notifications for the majority of apps that I have installed on my new 11 Pro – the only apps that appear to be sending me notifications are the ones that I've deliberately opened manually from my home screen – apps that I haven't yet opened since restoring from my iCloud Backup arn't producing anything – it's worth noting that they were working as expected after upgrading from iOS 12 to 13 on my XS before erasing it. So – things that I've tried so far:
Rebooting the phone
Checking the "Notifications" screen from within Settings.app – all notification settings are as they should be, and are enabled for apps that arn't currently producing them
Things that I deliberately haven't done yet:
Removed the apps that arn't currently producing notifications; I have a lot of these, and don't want to spend time re-organising my Home screen folders if I can avoid it!
Opening each app at least once to see if this begins to generate notifications (see my reasoning below for this)
So – my question. Upon restoring from an iCloud Backup, is it necessary to first open each app individually to force notifications to come through as they were doing before I restored? I have a lot of apps, but would prefer doing this than reinstalling them all individually. I don't remember having to do this when upgrading from my old iPhone 7 to the XS last year; I don't completely understand how APNS works, so can't figure out if my tokens will still be valid from my old iPhone or whether there's a simple solution to this that I just haven't tried yet. I'm not sure if the opening each app approach will work; I opened the Stack Exchange app upon restoring from iCloud to enter my login info, but as of yet haven't received any notifications – I know for a fact that I would have; I have new items in my Inbox that haven't come through as a notification on my new 11 Pro.
Best Answer
So - to answer my own question. It appears that after restoring from an iCloud Backup (I haven't been able to test with iTunes), that you have to open each app that you were previously receiving notifications for before restoring at least once - not performing this step means that they simply arn't generated, even though they're listed as being allowed to send notifications when checking from within Settings.app. I'm not sure why technically this happens - maybe somebody else has further insight which would be useful.