iOS 11.2.1 (build 15C153) is an official Apple over-the-air update for the iPhone 6+, released on 2017-12-13T18:12:42Z. The update package is 315.83 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: ef960b6e56b6f99d7a02a278de4821ae2a52e13a.zip.