iPadOS 9.1 (build 13B5130b) is an official Apple over-the-air update for the iPad 4 (WiFi), released on 2015-09-30T17:58:05Z. The update package is 159.85 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: 822679e6e930831962bd29ba30300340c2c414a4.zip.