iPadOS 9.1 (build 13B143) is an official Apple over-the-air update for the iPad 4 (Global), released on 2015-10-21T17:15:53Z. The update package is 922.6 MB. This is a delta (partial) update that requires 8.4 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 5c7b829fa74c551155265f1866ec4fcaec3ada5e.zip.