There are plenty of changes in this firmware that will make you update and loose jailbreak 3rd party apps. But for people like me, who doesnt want to activate on ATT, but have ATT account its a bit of a problem. Reading the #Iphone channel topic it states that “No Downgrade from 1.1.3 to 1.1.2 | No unlock for 1.1.2 | No 1.1.3 Jailbreak |Asking questions about either of these = kick | no support for *sim methods”. Which for me means no upgrade till the jailbreak.

 Check out this walk thru video of the new features (we already knew about them)