iPadOS 12.1 (build 16B92) is an official Apple over-the-air update for the iPad Air (Cellular), released on 2018-10-30T17:04:38Z. The update package is 1.21 GB. This is a delta (partial) update that requires 11.1.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 5728cb89d4db57fadcb617b222637ee21ec6ced2.zip.