iPadOS 11.3 (build 15E216) is an official Apple over-the-air update for the iPad Air (China), released on 2018-03-29T17:06:01Z. The update package is 583.68 MB. This is a delta (partial) update that requires 11.2.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 473a22f34748b162e7ba2e483bb53a8ef8607afe.zip.