I just found that some of my users stopped receiving push notification recently. Checked the log and found that Apple returned "Unregistered" with a timestamp.
I've tried using both old protocol and new HTTP/2 protocol with the same cert and token. The push using old protocol was received nicely, while the HTTP/2 one just returned "Unregistered".
The strange thing is not all my users failed, just some of them.
Anyone have idea on what's going on? Or face the same problem?
Thanks a lot!
