iOS 6 is, of course, compatible with the ; it can be also installed on last year's iPhone 4S, 2010's iPhone 4 and even the iPhone 3GS, now three years old. Also supported: the fourth and fifth generation iPod Touch, the iPad 2 and the Retina display iPad released in March. Not all models support all features, however. For instance, the iPhone 3GS may be able to run apps written for iOS 6, but it won't suddenly get access to Siri, which the Retina display iPad does. Outside the U.S., not all features are supported; Apple has information about each feature by region.

I tested and installed iOS 6 using an iPhone 4S, an iPad 2 and a Retina display iPad, and focused on features available in the U.S. market.

Before you head to Settings> General> Software Update to download iOS 6, it's a good move to first back up your iPhone to iCloud. Doing so will make it much, much easier to recover from any problems, if any crop up during the install. Performing an iCloud backup saves all of the data on your device, including details like app placement and settings, to Apple's online servers. (You can also plug your device into a computer and back up using iTunes. Be sure to download first.) Backing up is not a step I would skip.

Once that's done, . If the battery is at less than 50% capacity, you will have to plug your device in or the install won't begin.