iPadOS 9.1 (build 13B5136) is an official Apple over-the-air update for the iPad Air 2 (Cellular), released on 2015-10-06T17:54:05Z. The update package is 1.38 GB. This is a delta (partial) update that requires null already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 74268d47faed1737dac5ffc08ee7318de9908879.zip.