With today’s announcement, we’re pretty sure that iOS 5.1 will be right around the corner, with a probable release of the Gold Master sometimes this week.

A few people on Twitter asked me to put up a friendly reminder that jailbreakers should make sure not to update to iOS 5.1 when it comes out, especially iPhone 4S owners…

The Dev Team also posted a word of wisdom earlier today:

  • Soon after 5.1 appears on Apple’s public servers (i.e. iTunes starts to offer it), Apple will stop signing 5.0.1 SHSH blobs.
  • If you have an iPhone4S, the basic rule above is really the only rule:  you cannot restore back to 5.0.1 once the 5.0.1 signing window is closed, no matter what (even if you saved your SHSH blobs).
  • If you have an iPad2 with saved 4.x hashes, you can in fact downgrade to that 4.x but you won’t be able to get to 5.0.1 once the 5.0.1 signing window is closed (even if you saved your 5.0.1 SHSH blobs).
  • If you have a device earlier than the iPad2, you can downgrade to whatever version you want, as long as you have saved SHSH blobs for that version.  You’ll need the assistance of geohot’s limera1n exploit with tools like redsn0w to get into “pwned DFU mode” and bypass the downgrade restriction.

If you care about your jailbreak, the safest thing to do right now it to save your SHSH blobs and make sure you don’t update to iOS 5.1 when it comes out.