iPadOS 9.2.1 (build 13D15) is an official Apple over-the-air update for the iPad Air 2 (Cellular), released on 2016-01-19T17:59:38Z. The update package is 1.15 GB. This is a delta (partial) update that requires 8.1.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 12f4261c089910e6377228a3ef3039ad37732402.zip.