iPadOS 11.4 (build 15F5037c) is an official Apple over-the-air update for the iPad Air (Cellular), released on 2018-04-02T17:06:23Z. The update package is 225.18 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: 362b840f709acbc6239062e275a305706927af61.zip.