iPadOS 11.4 (build 15F79) is an official Apple over-the-air update for the iPad Air (WiFi), released on 2018-05-29T17:13:05Z. The update package is 214.8 MB. This is a delta (partial) update that requires 11.3.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 78e1d9a1ec29f56054fa2340ae521b2d967c84a3.zip.