I just upgraded from an iPhone 3GS to an iPhone 4S. Since then I have noticed that notifications for the Facebook app and the Xfinity app are very rare, even though they should be coming in. I've enabled notifications in both apps and have the notification center options turned on for both. Does anyone know if this is an iOS 5 problem, an iPhone 4S problem or something else? I don't think that I had this problem on my 3GS with iOS 5.