iOS 11.2.1 (build 15C153) is an official Apple over-the-air update for the iPhone 7 (Global), released on 2017-12-13T18:14:35Z. The update package is 1.19 GB. This is a delta (partial) update that requires 10.3.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 05b8a145bfd5d72df5217c7ca587419816721caf.zip.