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 922.68 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: 07978ecccc7601736d32cf5f05ef7e9094eac41e.zip.