iPadOS 11.2.1 (build 15C153) is an official Apple over-the-air update for the iPad Air 2 (Cellular), released on 2017-12-13T18:08:29Z. The update package is 1.1 GB. This is a delta (partial) update that requires 10.2.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 4803617afd544bf84562c065d12487746866bf21.zip.