iPadOS 9.1 (build 13B143) is an official Apple over-the-air update for the iPad 4 (GSM), released on 2015-10-21T17:15:53Z. The update package is 1006.92 MB. This is a delta (partial) update that requires 8.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 3b6ba52a1425d8042f64c759ccfbc26705c2aa6d.zip.