Apple is currently rolling out the first beta of iOS 8.1 to developers registered in Apple's iOS Developer Program. There’s no official change log, so it isn't entirely clear what we can expect from this update. However, we can expect it to bring various bug fixes to iOS 8.0 along with a few new features to the platform.
Apple is expected to bring Apple Pay to compatible devices in October, so its likely that iOS 8.1 will include this feature in some capacity. Apple Pay is obviously a big part of Apple’s mobile future, so we'll see how its new initiative turns out when it’s finally made available.
In addition to iOS 8.1 beta, Apple has also released a new Apple TV beta and Xcode 6.1 beta 3.
If you’re intrigued enough to try out the new beta but aren’t quite sure how to go about getting started, be sure to head over to developer.apple.com/ios, where you’ll find all of the necessary information. If you already have iOS 8 beta 3 installed, then you can also grab the beta 4 update from Settings > General > Software Update from your iOS device.