According to the latest trending report from Mixpanel, iOS 15 is now installed on nearly 86% of all iPhones. The latest trend report shows that the current production version of iOS is installed on 85.96% of iPhones with iOS 14 down to 9.75% and older versions of iOS down to 4.3%. With new iPhones continuing to be purchased, it is likely that iOS 15 will reach the 90% install mark overall but it remains to be seen if it will top iOS 14.
iOS 14, at its highest adoption level, was at 93.34% on September 13, 2021. Version 15 was released on September 20, 2021 and version 14’s decline began immediately. The adoption of the current release has been slower than previous versions so it is unclear if it will reach the 93% mark as its predecessor did. All things considered however, especially compared to the Android ecosystem, having the most current version of iOS installed on iPhones shows a level of trust with Apple and their ability to update older devices to the latest release.
All of this, of course, is with iOS 16 on the horizon. That version is expected to be released in September along with the new iPhone 14.