iPhone 6 iOS 11.4 Downgrade Closed
If your iPhone 6 or iPhone 6 Plus starts acting up on iOS 11.4.1, you're on your own.
Apple's stopped signing off on iOS 11.4 which means you can no longer take advantage of a loophole and drop down to the previous version of iOS 11 in an effort to improve performance.
Unfortunately, Apple's closed off all other versions of iOS 11 as well so once you move to iOS 11.4.1 you're stuck with it, and iOS 12 beta, until another version of iOS emerges.
If you aren't familiar with the downgrade process, take a look at our guide. It'll help you prepare for the next iOS update.