As we have discussed many times before that the ultrasn0w is broken on the latest iOS 4.3.x firmware and it needs an update to fix the broken status and some bugs to work smoothly on the latest iOS 4.3.1 untethered jailbreak, we have also reported before that after the release of Redsn0w and PwnageTool to jailbreak iOS 4.3.1. iPhone Dev team confirms that they will officially update the ultrasn0w to work on iOS 4.3.x. So today, MuscleNerd of iPhone Dev Team announced via twitter that new version of ultrasn0w is released to external testers and will release tonight to general public.
4.3.1-compat ultrasn0w update for *current unlockers* is out to external testers. Barring any hiccups, release is tonight
This is not a new ultrasn0w unlock, it only unlock the old baseband iPhone 4’s. This update of ultrasn0w 1.2 its just a compatibility fix of the application and also fixes the signal bar issue which occurs on iOS 4.3.1.