Jailbreaking has always been a cat and mouse game between Apple and jailbreakers alike. With Apples newest iOS 5.0 and up, newer devices such as the iPhone 4S, iPad 3 and even the iPad 2 have not been able to downgrade iOS firmwares.Meaning if a user accidentally updated they are stuck on the latest firmware without any way to downgrade even with SHSH blobs saved.
It now appears that Redsn0w will be updated to bring downgrading with SHSH blobs to the newer devices. Check out what MuscleNerd said after the break.
“Upcoming redsn0w supports restoring, including iPad 2/3 and 4S downgrades (with blobs) http://twitpic.com/9ixsqv ..also stitches on the fly :)”
Downgrading is important in regards to jailbreaking because it allows them to go down to a firmware that has an untethered jailbreak. The most current one is iOS 5.0.