According to Apple iOS 9 is the fastest adopted iOS update ever, with over 50% of active iDevices running on the latest version of the OS as measured by the App Store on 19 September 2015.
“iOS 9 is off to an amazing start, on pace to be downloaded by more users than any other software release in Apple’s history,” Apple senior VP Philip Schiller says.
The update was released on 16 September, and brings along a series of under the hood changes, such as more powerful search and Siri features. It is compatible with iOS 8 devices-- meaning the iPhone 4S onwards, 5th generation iPod Touch, iPad 2 onwards and iPad Mini 1st generation onwards.
Apple adds iOS 8 was installed on 87% of compatible iDevices just 2 days before the iOS 9 launch.