iPadOS 11.4 (build 15F5077a) is an official Apple over-the-air update for the iPad Air (Cellular), released on 2018-05-14T17:16:42Z. The update package is 222.83 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: 14f54acaaacc3131cd984d129e307abc5cfd9d0e.zip.