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 962.85 MB. This is a delta (partial) update that requires 8.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: e5b6a5590a9d465dd9d1e46d8ebde1fd053bb0a1.zip.