I called ATT , after my HTC One (which I guess is an M7, it's older) one day decided a new version was available and downloaded and installed it on the phone....I HATE some of the changes...before , a double click on the home button brought up nice, easy to see small, rectangular icons of every open app...now it's this bizarre and unwiedly scrolling look, no good....Much more aggregious, has been the horrible performance drop...apps hang and freeze, the worst is texting with the default texting app..a hanging delay occurs everytime I try to send a text to anyone and then it flat out boots me out of the ap!..Every time. There are other noticeable worse things but these I remember off the top of my head.........makes me wonder, do people look forward to OS updates for no other reason than they think they need the latest version, just because it's the latest version? lol....Anyway, the ATT tech admitted they have gotten MANY call complaints after their phones updated to this 'lollipop' (who NAMES these ? lol) OS update...They said they can't do anything about it , but can only hope the powers that be release a newer update that fixes all the horrible crap changes and poor performance...