iPadOS 11.2.1 (build 15C153) is an official Apple over-the-air update for the iPad mini 4 (WiFi), released on 2017-12-13T18:07:25Z. The update package is 356.08 MB. This is a delta (partial) update that requires 11.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 46ef28c8ac2b0387f2d9d4ae31155ada387acda3.zip.