iPadOS 9.1 (build 13B143) is an official Apple over-the-air update for the iPad Air 2 (WiFi), released on 2015-10-21T17:15:59Z. The update package is 240.99 MB. This is a delta (partial) update that requires 9.0.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: d6850ec21b1b67c1ad8c4ff105c4642f1bb325d1.zip.