iPadOS 11.2.1 (build 15C153) is an official Apple over-the-air update for the iPad Air (China), released on 2017-12-13T18:04:38Z. The update package is 327.27 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: 86e4d907b50cd1b4f76c12dd05f5e95cf086a1a8.zip.