Apple's App Store Usage Numbers Put iOS 7 Adoption at 80%
As iOS 7 adoption numbers grow, iOS 6 usage continues to drop, and the older operating system is now installed on just 17 percent of devices. Three percent of devices also continue use even older versions of iOS.
In early December, iOS 7 usage was at 74 percent, jumping to 78 percent later in December, while iOS 6 usage first declined to 22 percent and then to 18 percent.
Apple's data, which comes directly from the App Store, represents the most accurate iOS 7 adoption information for developers.