I have an iPhone 4 that had the battery swell and pop the back. I visually looked over everything else and it seems fine. I lost the 2 screws that hold the back on...but.....that's ok. What I am wondering, since its been AGES since this has been fired up, What is the latest IOS that would work smoothly on this so I can re initialize it for my Mother in law so we can face time when on vacation. I think everything else is fine after I pop a new battery in it.