iPadOS 12.1 (build 16B5084a) is an official Apple over-the-air update for the iPad Air (China), released on 2018-10-15T17:02:52Z. The update package is 329.52 MB. This is a delta (partial) update that requires 12.0 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: fd41a7388b5f89d5b6233f0269d478a9cb810e0d.zip.