iOS 11.3 (build 15E216) is an official Apple over-the-air update for the iPhone 7 Plus (GSM), released on 2018-03-29T17:13:36Z. The update package is 1.48 GB. This is a delta (partial) update that requires 10.3.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 987d9c9b7a23f133429f4c42c67bf0ffe79a2e60.zip.