According to Apple’s App Store distribution dashboard, 81 per cent of iPhone and iPad owners are now using iOS 8, which is a 4 per cent increase since March and an 8 per cent increase since February. At 17 per cent, devices running iOS 7 make up a still significant portion of Apple’s user base. The remaining 2 per cent is attributed to “earlier” versions of iOS. These stats are based on the data collected from users that visit the App Store, and is mainly compiled for the platform’s developer community.
It’s possible that jump in iOS 8 adoption is due to the fact that the OS is mandatory if someone wants to pair their Apple Watch with an iPhone.