I have to agree, I first got this phone and it came with iOS 11. Cheap phone for 80$, so I couldn’t risk it! Got the phone, didn’t come with a charger. All in all, purchased a new battery for 10$ and I have seen better improvements on the battery but not by much. Only by an hour and a half. It has to do with the update. My phone gets warm when running all apps. And that means the battery is overpowering and it has to much data to handle. (At least what I think.) even when people give me a suggestion to power my phone off every time I use it — well, by the time it reaches 40% battery life remaining and I power it off, just because of that single power off, it will shut down completely and say it’s dead... this is totally apples fault.