At the WWDC 2018 developer conference, Apple announced the new generation of iOS 12! Cook said that today is talking about software, it looks like the ipad, MacBook, Homepod, iphone, nothing will be updated, the Apple Store has not been maintained.
IOS 12 will not make too much of a functional change, pay more attention to performance, especially the performance of the old device, known as application startup Speed 40%, keyboard start speed 50%, the camera start speed 70%.
This is largely due to CPU processor scheduling optimization, see this means that the old device will not deliberately drastically reduce frequency. iOS 12 will maintain good old device compatibility, and iOS 11 support iOS 12 continues to support all of it.