iPadOS 11.3.1 (build 15E302) is an official Apple over-the-air update for the iPad Pro 12.9-inch (WiFi), released on 2018-04-24T17:08:41Z. The update package is 1.27 GB. This is a delta (partial) update that requires 10.3.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: ef2578fef57c604ce43e43332abdc9d7475760d8.zip.