iPadOS 9.2.1 (build 13D15) is an official Apple over-the-air update for the iPad 4 (WiFi), released on 2016-01-19T17:59:13Z. The update package is 910.79 MB. This is a delta (partial) update that requires 8.4.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: cd5431e98b04bca8baf56e0b95d8f2000a1e2548.zip.