While it’s still light years ahead of Android Oreo’s adoption (which is currently at 0.2 percent), there is a drop in the number of iOS devices running iOS 11. The latest version of iOS is currently installed in 52 percent of iPhones and iPads, according to Apple’s App Store support page for developers. Last year, iOS 10 reached 60 percent of devices, while iOS 9’s adoption rate was at 67 percent by November 16, 2015.
This slower rate of adoption though could be attributed to a number of factors. One is there have been bugs plaguing the operating system. Another is it’s seen as an iPad-focused update so less iPhone users see the need to upgrade.
Source: The Verge