iOS 11.3 (build 15E216) is an official Apple over-the-air update for the iPhone 7 Plus (GSM), released on 2018-03-29T17:13:38Z. The update package is 740.1 MB. This is a delta (partial) update that requires 11.2.6 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: f3fb9c7abe6f9336223c0f377808316bd019d992.zip.