• SMS Relay – this means that on Macintosh computers running Yosemite and iOS devices running iOS 8.1, you can now send and receive SMS text messages via both the device and the Messages applicaion on Macintosh computers. The caveate here is that the computer must have upgraded to Yosemite and your device must be running iOS 8.1
• Instant Hot Spot – With this feature running, it simply means that when a Macintosh computer running Yosemite is in proximity to an iPhone that is creating a “hot-spot” connection to the Internet, the computer will be able to use the hot spot and connect. Via MacRumors, “This feature lets a Mac remotely activate the Personal Hotspot capabilities of an iPhone when the two devices are near each other. The Mac can automatically detect an iPhone with Hotspot and users can connect to a Hotspot via the Mac’s Wi-Fi menu without needing to remove the iPhone from their pocket.”
• Apple Pay – This is Apples new electronic payment system that can be used on your iPhone. See more information here.
• The Cameral Roll will return in iOS 8.1 (yes, is was removed in iOS 8.0) and also iCloud will set up the iCloud Photo Library. Via MacRumors: “iCloud Photo Library is tied to a user’s iCloud account, using the storage space of their iCloud plans. With iCloud Photo Library, photos are kept in the cloud with a smaller version available on iOS devices, taking up less storage space. iCloud Photo Library will also tie in to the upcoming Photos app for the Mac, but until that is available, iCloud Photo Library will only be available on iOS devices.”

These are the updates that are coming out today with the release of iOS 8.1. You can upgrade via iTunes or also via the device itself under: Settings – General – Software Update.