iPadOS 11.3.1 (build 15E302) is an official Apple over-the-air update for the iPad Air (Cellular), released on 2018-04-24T17:05:10Z. The update package is 1.24 GB. This is a delta (partial) update that requires 10.1.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 7d03aa855f77e7a841cee1e15675ba7bbf15006b.zip.