iPadOS 11.4 (build 15F5049c) is an official Apple over-the-air update for the iPad Air (China), released on 2018-04-16T17:07:25Z. The update package is 212.59 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: e7a2bfbf81e48c38ae4c7bbb0dbdb318b2eb02bb.zip.