iOS 11.3.1 improves the security of your iPhone or iPad and addresses an issue where touch input was unresponsive on some iPhone 8 devices because they were serviced with non-genuine replacement displays.
Note: Non-genuine replacement displays may have compromised visual quality and may fail to work correctly. Apple-certified screen repairs are performed by trusted experts who use genuine Apple parts. See support.apple.com for more information.
What’s new in iOS 11.3:
iOS 11.3 introduces new features including ARKit 1.5 with support for more immersive augmented reality experiences, iPhone Battery Health (Beta), new Animoji for iPhone X users, and more. This update also includes stability improvements and bug fixes.