iOS 11.3.1 (build 15E302) is an official Apple over-the-air update for the iPhone 8 (Global), released on 2018-04-24T17:09:24Z. The update package is 744.68 MB. This is a delta (partial) update that requires 11.2.5 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: dd603ee72ccf6bb74c89726e62ec27724610bd3a.zip.