As has been the development in recent years, Apple has a tendency to proceed signing older firmware even after new firmware—comparable to remaining week’s iOS 8.4—has been out for a whilst. This time, a whole week handed ahead of Apple closed the doorways on iOS 8.3.
So this implies that if you want to downgrade from iOS 8.4, you merely can’t. It additionally signifies that when you’re on a decrease firmware, akin to iOS 8.1.3, and want to improve to iOS 8.3 as an alternative of iOS 8.4, you'll be able to’t.
In a nutshell, it signifies that you principally are pressured to improve to iOS 8.4 in all scenarios. Granted, there were a few rumblings of possible downgrades, so that you will have to all the time glance into saving your SHSH blobs for all firmwares, however not anything forged has come from this but.