iOS 11.3 (build 15E216) is an official Apple over-the-air update for the iPhone 7 Plus (GSM), released on 2018-03-29T17:13:35Z. The update package is 1.53 GB. This is a delta (partial) update that requires 10.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 24bcd701181f06d91603e3e24cca88b260c5670f.zip.