iPadOS 11.4 (build 15F5037c) is an official Apple over-the-air update for the iPad 5 (Cellular), released on 2018-04-02T17:06:37Z. The update package is 233.75 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: 12f24a3183a537113d38e2d535b1c3720ea1ba2c.zip.