iOS 11.3.1 (build 15E302) is an official Apple over-the-air update for the iPhone 8 (Global), released on 2018-04-24T17:09:25Z. The update package is 45.28 MB. This is a delta (partial) update that requires 11.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 285ad66b7d5e382a08265a51d689774cc52fcdfa.zip.