iOS 11.3.1 (build 15E302) is an official Apple over-the-air update for the iPhone 8 Plus (Global), released on 2018-04-24T17:09:27Z. The update package is 806.99 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: ca7f031536ddc9ce4cbfbcbf2537d5f8cea78786.zip.