iPadOS 9.1 (build 13B5119e) is an official Apple over-the-air update for the iPad 4 (GSM), released on 2015-09-23T17:55:04Z. The update package is 144.04 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: 4064d5703505704f0b1163e5ea72d5bc02dbd556.zip.