iOS 4.3.1 has just made the scene out of no where. There were neither beta tests nor big keynotes about it, and that’s because it barely fixes a few bugs.
Issues with enterprise apps, AV-out, iPod touch graphics problems, and cellular network connections were addressed, but that’s about it. Our advice is that you stay away if you intend to Jailbreak your device in the future, since a lot has been said about this update closing the door to some of the exploits needed to get it working.
If that still doesn’t pull you away from using the latest and greatest iOS software, connect your iPhone to your computer and hit “Check for update” in iTunes.