Are you experiencing network service issues with your iPhone lately? How about video streaming crashes or problems with your iPhone not waking up from sleep mode? If the answer to any of these questions is a yes, you’d be happy to know that Apple's latest firmware release, iPhone OS 3.1.2, specifically addresses these issues.
It's now available in iTunes, and is compatible with all versions of the iPhone. Of course, even if you’re not experiencing any of the aforementioned problems, there’s no reason for you not to update to iPhone OS 3.1.2 as this should also improve over-all performance.
That is unless you’re using a jailbroken and unlocked iPhone. If so, you should exercise some patience and stay clear of this update for the time being. The iPhone Dev Team has already issued a statement regarding this latest firmware release and goes on to say that their current jailbreaking tools (PwnageTool 3.1.3, redsn0w) will not work with iPhone firmware 3.1.2. They made an assurance that they'll come out with an appropriate jailbreak solution soon but didn’t mention a date as of yet.