The long-awaited update to iOS 4.0 is showing signs that it will soon be released to the public. iOS 4.1 is now available for Registered Developers to download in the Apple Developer Center
The update has been confirmed to fix the reception problems commonly found with the iPhone 4 (and some older devices) when held with a death grip.
The change will adopt a recently recommended formula from AT&T that will more accurately display actual signal strength at any given time. The update will also increase the size of the smaller bars (1, 2, and 3) to make them easier to see.Though Apple claims that this update should solve reception issues, many are claiming that the issues are much larger than just software - they could be a result of the new antenna design.
If you are jailbroken on iOS 4.0, don't update to 4.1 until an official jailbreak is released.
Update: MobileCrunch has tested the new iOS 4.1 and it in-fact does not fix the iPhone 4's reception issues.