Hours after the release of iOS 8.0.1 Apple pulled it. It’s not always great to be first to upgrade your device. Still Apple released and pulled the flawed Update 8.0.1 before it did some damage.
The update scrambled the Touch ID not letting users into the iPhone. The iPhone also runs searching loop that expunged cellular service. Others reported that the messages app is also corrupt.
There are always issues with upgrades and updates. It’s a good thing Apple is always on top of it.