This post is a little longwinded but I want to describe my issues in detail for anyone else experiencing the same incredibly frustrating problem. I've had my 6s (64gb, SG, Verizon) since launch day. I didn't have any issues until I updated to iOS 9.3.2. After that my battery life was horrible. I have an Apple Smart Battery Case that I use for long trips (business travel) and after 9.3.2 I was using it every day just to get through a normal work day. On long days I was completely draining both and plugging in. Naturally I assumed it was a software issue. I tried several restores, including DFU restore to no avail. I closely monitored the battery stats in settings but they all appeared normal. I figured an app must have gone rogue during the update and I spent the next few months trying to figure out which one. After updating to 9.3.3 the problem got even worse. On several occasions the battery would drain rapidly, like down to less than 20% within a couple hours. If I did a hard reset, the phone would power back on and the battery indicator would read a much higher percentage after restart (18% to 30% for example). Friday the phone randomly shut off at around 32% then powered back on showing 46%. It was exhibiting the same behavior as my wife's iPhone 5 back when they had battery recall/replacement program. I contacted Apple support by chat and they remotely ran a diagnostic (which was pretty neat). After looking over the data they said that there was a "known hardware issue" causing the problem and they issued me a replacement phone that I could pick up at the local Apple Store. When I went in to pick it up, I asked the tech at the store if a lot of people were having the same problem with the battery and he said "It isn't the battery, the battery is testing fine." He scrolled through some of the diagnostic data Support had pulled from my phone on his iPad and said "There isn't a recall or anything. I don't know what it is exactly, but I've seen it enough times to know the only way to fix it is replacing the phone. It must be a problem with the logic board or something." I took my new phone home, updated to 9.3.3, restored from an encrypted backup on my Mac and my battery life has been amazing. It was off the charger all day yesterday (7am to 11pm) and I still had about 30% left when I went to bed. No clue how a software update would trigger a hardware problem like that, or maybe it was just coincidence. The only hardware difference I can see is that the first phone had a Samsung A9 and the new one has a TSMC A9. No idea if that is part of it, just figured it was worth mentioning.