iPadOS 11.3.1 (build 15E302) is an official Apple over-the-air update for the iPad Pro 9.7-inch (Cellular), released on 2018-04-24T17:08:35Z. The update package is 683.93 MB. This is a delta (partial) update that requires 11.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: b4e3057f72dd5fe8215e17542f72939619ed5121.zip.