I 'upgraded' i think on Sunday - 13th November.I've had the phone since the 6S release date & the battery life has been impressive really On iOS 9.3.5 the battery usage was pretty much the same throughout.... Charge the phone at night, take off charge. Wake up ... 100%. Use at breakfast ... 97%. 11am break at work ... maybe 95% 1:30pm break at work .... maybe 60% (by the end of the break as i'd use it quite a bit then) 5:30pm hometime ... somewhere around 50-55%. And that was the same ... day in, day out Like i said, i upgraded to iOS10 on Sunday. Monday wasn't too bad. Worse than the iOS9 days but nothing major. The past few days though have been shockingly terrible. The phone is almost useless. So i would wake & the phone would be 100%. Use at breakfast .... 85% yesterday at 11am break it was 56%, today at 10am (i took an early break) it was 11%. Yes, 11%, from 85% at 6:30am!! At 1:30pm break yesterday it was 11%. Today by 12pm (again early break today) it was 2%!! Oh & on Monday it died from 50%. Both yesterday & today after first break i would turn it off, turn it on & it would read about 60-70%. Then the second break after it had dropped to pretty much single figures i would do the same but this time it would stay in single figures. I've turned off things to save battery. For example i've removed all widgets. Turned off lift to wake & things like that. I always close all apps after break. Location services don't appear to be tracking anything in the background. And it's been night & day - ok with iOS9 but as soon as i went to iOS10 it's been terrible. Not really sure what to do next.