iPadOS 9.1 (build 13B143) is an official Apple over-the-air update for the iPad Air (WiFi), released on 2015-10-21T17:15:54Z. The update package is 235.37 MB. This is a delta (partial) update that requires 9.0.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: e6537f210817129d759c246539655c21c1d2f12b.zip.