Based on user feedback Apple's update for iOS 8 is a mix of features that did not make the official launch of the original software, like the return of Camera Roll.
Though, bringing back Camera Roll back does eliminate few confusion in iOS 8.1 device media management, though I must confess I was never left all that confused by its absence in the first place. As for Apple Pay, while it seems like the feature launch in iOS 8.1 with the most long-term potential, initially it’s going to be limited by retail availability, and also the fact that it’s U.S.-locked – a fact which means I won’t have a chance to trial it in a real-world situation for the time begin. In staged demos with live terminals, however, it performs very well.
To get the iOS 8.1 update is available over-the-air update, which you can find by heading straight to Settings > General > Software Update; you can also plug your phone or tablet into your computer and update via iTunes, which might be preferable if you’re still on an OS version earlier than 8.0, since the size requirements for over-the-air are significant. To use the new Continuity features with your Mac, you’ll have to download and install OS X 10.10 from the Mac App Store, which is a free update