Users of older iPhones who have upgraded from iOS 8 to iOS 9 report that some of their apps stop working when connected to a cellular network, rendering their iPhones nearly useless when they're out and about and not connected to a Wi-Fi network.
The problem was first reported by Wayne Williams of Beta News, who says that toggling the settings to allow certain apps to work over cellular data does not work. The toggle, which can be found in Settings > Cellular > Use Cellular Data For, simply switches itself off when he leaves the Settings app, Williams says.
"Not a major deal you might think, but actually that limits what I can do when not connected to a wireless network," says Williams.
For instance, Williams says he can no longer use Facebook to check in to places or update his friends about where he is. He also can no longer get directions from Google Maps or Apple Maps and check the news and weather without connecting to Wi-Fi.
The issue appears to affect apps that were not allowed to access cellular data in iOS 8. However, as pointed out by other users who have taken to Apple's support forums to report the problem, apps that were allowed to access cellular data in iOS 8 continue to be able to access cellular in iOS 9.
"I'm having exactly the same issue," says one user. "Any apps that were switched off for mobile data use before the iOS 9 update will not now switch back on. I've reset network settings to no avail. Deleting the apps and reinstalling them doesn't seem to work either."
Plenty of other users have taken to Twitter to voice their complaints.