You might know that Apple released iOS 4.3.5 yesterday to fix some security vulnerability with certificate validation. And with the release of this update, we advise you not to update your device to 4.3.5 if you care about your jailbreak or unlock. If you don’t rely on jailbreak or unlock, then you can update otherwise, just stay away. MuscleNerd, member of iPhone Dev Team also announced on his Twitter account to stay away form this update.
You can still jailbreak iOS 4.3.5 using RedSn0w except on iPad 2 , but it would be a tethered jailbreak, which means that you will have to connect your device to your computer to tether boot it every time you restart or turn off your device. But the moral of the story is ‘Don’t update if you rely on jailbreak and unlock’