iOS 11.3 (build 15E216) is an official Apple over-the-air update for the iPhone 7 (Global), released on 2018-03-29T17:13:20Z. The update package is 737.94 MB. This is a delta (partial) update that requires 11.2.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 875127b63587ca424d830c48b999fd603f2a0a31.zip.