iOS 11.3.1 (build 15E302) is an official Apple over-the-air update for the iPhone 8 Plus (Global), released on 2018-04-24T17:09:28Z. The update package is 750.8 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: ceaad070f77d9d0a9863f33a4f83e7e988c543f0.zip.