Asking here instead of the Dev. forum because I can. This is my first transition to a iOS version. With the .ipsw files downloaded from the Dev Portal, how long am I able to downgrade to iOS 6? I've never JB but I've seen lots of posts on backing up SHSH blobs. Is that necessary to jump back and forth between iOS 6 and iOS 7 for an undetermined amount of time? Or is being a registered Dev with the appropriate files enough? Thx.