iPadOS 11.3 (build 15E216) is an official Apple over-the-air update for the iPad Pro 12.9-inch (Cellular), released on 2018-03-29T17:10:54Z. The update package is 678.32 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: bf6f1b8f5efc087d16a094d3f169e0fbdba6fa8f.zip.