iPadOS 11.2.1 (build 15C153) is an official Apple over-the-air update for the iPad Pro 12.9-inch (Cellular), released on 2017-12-13T18:10:02Z. The update package is 1.08 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: e8b75465cd6a7da8de508665f14cc4485db4f688.zip.