Several users have taken to Apple Support Forums complaining about rapid battery-drain issues after upgrading their iPhone to iOS 10.1.1. iPhone users are reportedly experiencing reduced battery life with as much as 60% battery drain occurring in idle mode or even when the device is turned off.
Some other users are reporting that their iPhones are shutting down abruptly even with 30% battery charge still remaining. Quite strangely, the device seems to boot up just fine when it's connected to the power outlet while also showing up enough battery charge on the handset.
"I have the same problem with my iphone 6 DYING SUDDENLY at 30% battery, using ios 10.1.1. This did not happen with ios 9 but it's too late, I can't go back now... believe me I have tried to downgrade multiple times! I can't even go back to 10.1 because I need to restore all my apps from my backup which requires 10.1.1," says user helpmetohelpyou on Apple Support Forums.
It is evident from the various user posts on the complaint thread that the issue is not isolated to any particular iPhone model. But, all handsets from iPhone 5 through iPhone 7 are allegedly facing the battery drain problems, following the iOS 10.1.1 update.
Although there is no official fix for this issue yet, some veteran iPhone users have suggested that disabling Raise to Wake feature has helped them to increase the battery life on their iPhone 6s and iPhone 7.
Meanwhile, some other users have resorted to installing beta builds of the next iOS 10 update with hopes of temporarily resolving this issue.