iPadOS 11.4 (build 15F5079a) is an official Apple over-the-air update for the iPad Air (China), released on 2018-05-17T17:01:52Z. The update package is 222.88 MB. This is a delta (partial) update that requires 11.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: d907e4fafef35528e2b087a54f111bcaea841499.zip.