I had all kinds of issues with this update. So just wanted to share my experience. Downloaded the update via OTA had serious problems with battery life as well as lag and other odd crazy stuff. I wiped the cache partition several time to no avail . Then I did a factory reset with backup options . still had issues then a factory reset without backup option. Still problems . Finally I used KIES it showed I had the current version but I clicked ok Update firmware anyway and sure enough it reloaded the update via KIES . I then updated everything in the play store. Once that was done then I started re downloading all my apps from playstore instead of using the backup file on kies. This Fixed all my problems and everything is running perfect battery life is better than kitkat and phone is much faster. So there's my story maybe it will help someone.