iPadOS 9.9.11.2.1 (build 15C6153) is an official Apple over-the-air update for the iPad Pro 12.9-inch (Cellular), released on 2017-12-13T18:03:12Z. The update package is 1.76 GB. This is a full OTA update that can be applied from any compatible base version. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 83c403e30b6895b0b23b5e01b42b09fe9499f582.zip.