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 https://support.apple.com for more information.

For information on the security content of Apple software updates, please visit this website: https://support.apple.com/kb/HT201222