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 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 3a00fe35da4007b4b2bb9dbad8fb1c55f7bc4965.zip.