Receiving duplicate push notification ios9
I had this problem in several apps, and looks like duplicates appear if you call registerUserNotificationSettings: more than 1 time.
More details in this answer:https://stackoverflow.com/a/35064911/4495995
It is apparently an Apple issue. I've faced the same issue many times across apps. https://forums.developer.apple.com/thread/13414
From iOS 9 every time when you uninstall and than re-install the app again a new device token has assigned this might be the reason that you receives the multiple push notifications.
Actually I read out from one forum, they provide the solution that when you generating a payload that add one extra custom any random value so that each payload has some unique value. in my case in vb.net I am using DateTime.Now.ToString("MMddyyyyHHmmssfff") to add a unique time stamp with milliseconds. I hope its work I implemented this but not tested so far.