iPadOS 9.2.1 (build 13D14) is an official Apple over-the-air update for the iPad mini 4 (WiFi), released on 2016-01-04T17:58:48Z. The update package is 34.61 MB. This is a delta (partial) update that requires 9.2.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 432eb4f708384196a90f405d957ed0e28a0bf3fe.zip.