Apple has updated their adoption statistics on their developer page, showing that 88 percent of active iPhone, iPad, and iPod touch devices are running iOS 12.
Apple’s data shows that 90 percent of devices introduced in the last 4 years are now using iOS 12. The remaining 10 percent is split between iOS 11 (7%) and earlier operating systems (3%.)
Apple’s data shows that 88% of customers are running iOS 12, 7% are running iOS 11, and 5% are still holding on to earlier iOS releases (likely using devices that cannot update to iOS 11 or later).
These iOS upgrade rates represent an increase compared to the iOS 11 cycle. At approximately the same time in the cycle in 2018, iOS 11 adoption was at the 85% level.