iPadOS 9.1 (build 13B143) is an official Apple over-the-air update for the iPad Air 2 (Cellular), released on 2015-10-21T17:15:59Z. The update package is 1.14 GB. This is a delta (partial) update that requires 8.1.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 94d3437b38dc02a8a397447880d36f2a93ed9feb.zip.