iPadOS 9.9.11.2.1 (build 15C153) is an official Apple over-the-air update for the iPad Air (Cellular), released on 2017-12-13T18:03:46Z. The update package is 1.45 GB. This is a delta (partial) update that requires 8.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 02c3f24148831f9c9f581cbec3c706eaa69f26c6.zip.