iPadOS 11.3.1 (build 15E302) is an official Apple over-the-air update for the iPad 5 (WiFi), released on 2018-04-24T17:08:00Z. The update package is 745.85 MB. This is a delta (partial) update that requires 11.0.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 614c280f28382c9084f00df86cd2d6d10b3fc1d3.zip.