iPadOS 9.1 (build 13B143) is an official Apple over-the-air update for the iPad Air (Cellular), released on 2015-10-21T17:15:54Z. The update package is 252.94 MB. This is a delta (partial) update that requires 9.0 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 4c40d6ec635ec51bf210c888a0bffdde3cc7967d.zip.