https://www.theverge.com/2017/11/16/16667304/ios-11-update-iphone-x-cold-screen-unresponsive-fix-apple

Apple has just released iOS 11.1.2, which, as promised, fixes an issue where screens on iPhone X devices could become unresponsive in cold weather. Afflicted users noted reports of iPhone X displays freezing up when suddenly taken outside into cold environments, before resuming normal activity a few seconds later.

The fix is a pretty fast turnaround for Apple, which acknowledged the issued far sooner than usual when reports of the problem first emerged last week. Along with the screen fix, iOS 11.1.2 also patches a problem where live photos and videos shot on an iPhone X could become distorted.