Installed 6.1.2. and found battery life chronic afterwards. From full to empty in 3 hours and was quite hot. I nearly took it a store but thought id give anything a try. ALL backed up save points did the same. Set up as new Iphone then used icloud back for contacts and mail. Then selected apps from cloud. It seems that if you take an update over the air the phone behaves differently from itunes upgrade. It just takes a bit more time to add apps.