iOS 11.3.1 (build 15E302) is an official Apple over-the-air update for the iPhone 7 Plus (Global), released on 2018-04-24T17:11:29Z. The update package is 745.21 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: 43802c4db67c6f5d2a7fe59ed998bb225fd8cda1.zip.