iOS 11.3.1 (build 15E302) is an official Apple over-the-air update for the iPhone 8 (Global), released on 2018-04-24T17:09:23Z. The update package is 797.94 MB. This is a delta (partial) update that requires 11.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 5cf765a1eef8776e4db48d745e23bc8eda385619.zip.