iPadOS 11.3.1 (build 15E302) is an official Apple over-the-air update for the iPad Pro 12.9-inch (Cellular), released on 2018-04-24T17:08:50Z. The update package is 1.3 GB. This is a delta (partial) update that requires 10.3.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 3c9636112eee2a7623897e7549f49fb1afe9478d.zip.