iOS 11.2.1 (build 15C153) is an official Apple over-the-air update for the iPhone 7 Plus (GSM), released on 2017-12-13T18:15:15Z. The update package is 396.45 MB. This is a delta (partial) update that requires 11.1.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 7fb5c906415ac6b4d35579a8b27ee421e604d801.zip.