We’d usually advise jailbreakers to avoid Apple’s iOS updates just after their release, until hackers have confirmed that the latest software can be jailbroken. But one report claims that it’s perfectly safe to update your A4-powered devices to iOS 5.1.1 without losing your Redsn0w jailbreak.
iOS 5.1.1 Update Doesn’t Kill The Redsn0w Jailbreak For A4 Devices [Jailbreak]