https://www.theverge.com/2018/6/4/17417730/apple-ios-12-iphone-update-best-features-wwdc-2018

We knew coming into WWDC that iOS 12 would focus less on major new features and more on improving performance and eliminating bugs, and that’s definitely the case based on what Apple showed onstage today. “For iOS 12, we are doubling down on performance,” said software VP Craig Federighi. But the new update for iPhones and iPads does include some changes and improvements that you’ll notice when you install it this fall (or sooner if you join the beta). iOS 12 will be available on all the same devices that received iOS 11.

Apple is working to make iOS feel faster than ever — particularly on older iPhones and iPads. Federighi said that apps launch 40 percent faster, the system keyboard comes up 50 percent faster, and opening the camera is 70 percent faster on older devices. Apple is working to make improvements for all iOS devices when they’re under load and being used heavily.