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 747.86 MB. This is a delta (partial) update that requires 11.2.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 343cc5141e81c2edec7aa0ff98b6da83f59cc0f1.zip.