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 190.2 MB. This is a delta (partial) update that requires 9.0 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: d03312d90a7b3f06d15b75c769daec41c3e0fe85.zip.