iPadOS 11.2.1 (build 15C153) is an official Apple over-the-air update for the iPad Air 2 (WiFi), released on 2017-12-13T18:08:14Z. The update package is 356.06 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: e9a1f5032ff46146199eb39bd4f8ab0512672b35.zip.