iPadOS 11.3 (build 15E216) is an official Apple over-the-air update for the iPad Pro 12.9-inch (WiFi), released on 2018-03-29T17:10:44Z. 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: 4bd50678d993fc0ec36985d4c7e60dfab7b0921c.zip.