iPadOS 9.9.11.2.1 (build 15C153) is an official Apple over-the-air update for the iPad Air (WiFi), released on 2017-12-13T18:03:41Z. The update package is 1.22 GB. This is a delta (partial) update that requires 9.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: a8e6a0c0132c72864019660b13c4b2e734196689.zip.