Battery life? ******. That's the sad truth. I upgraded to iOS 12.3.1 and it ruined my dear 6s. LTE has come down 2 bars and there's nothing I can do. And it will surely not make me buy a new iPhone. Au contraire. It's slower and battery life has gone crazy. I'm done with iPhones. I'll keep this old fart and that's it. Now, for all of you that iOS 12 have done miracles, please tell me what I've done wrong. I use only Apple apps not even Facebook and Instagram. I thought about wiping the damn thing and starting from scratch.