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 755.27 MB. This is a delta (partial) update that requires 11.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 3c0a0d5a7491048a539bf3966ecdda3aa0f58077.zip.