iPadOS 9.1 (build 13B5130b) is an official Apple over-the-air update for the iPad Air 2 (WiFi), released on 2015-09-30T17:58:09Z. The update package is 194.23 MB. This is a delta (partial) update that requires 9.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: abc20469b94b67878996c7a69bf96268de823bb5.zip.