Crazy situation! My battery drain seems slightly worse than 8.2 but my mail usage is way high. After installing 8.3 from 8.2 I noticed my mail and battery usage slowly increasing. My battery usage will usually go up after an update due to increased usage but will quickly go back to normal. My mail numbers have never increased before. I checked this post and noticed a user have the same issues. I did all that was recommended. Such as erasing my emails and doing a hard reset then reinstalled with no luck. I also reset network settings with no luck. My mail settings are set to fetch and 30 minutes. Nothing is set to push. Finally I erased the two emails I have, not including iCloud mail, and tried to hard reset again. I'm going to give it a day and see if the mail rate goes down but does anyone have any more suggestions? Thank you