iPadOS 11.3.1 (build 15E302) is an official Apple over-the-air update for the iPad Pro 2 (12.9-inch, WiFi), released on 2018-04-24T17:08:58Z. The update package is 599.49 MB. This is a delta (partial) update that requires 11.2.6 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 39a3f278d3f208676631cfd38b208ab8817146aa.zip.