iPadOS 11.2.1 (build 15C153) is an official Apple over-the-air update for the iPad Pro 12.9-inch (Cellular), released on 2017-12-13T18:10:01Z. The update package is 1.14 GB. This is a delta (partial) update that requires 10.3.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: e30711a3ba7c5d1f50d2a9627ca5856ea0bb5162.zip.