iPadOS 11.3 (build 15E216) is an official Apple over-the-air update for the iPad Air (Cellular), released on 2018-03-29T17:05:52Z. The update package is 577.97 MB. This is a delta (partial) update that requires 11.2.6 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 5ffee4fcf0bbabb1ac7fe3e9d088947b8a8eb94c.zip.