iPadOS 11.2.1 (build 15C153) is an official Apple over-the-air update for the iPad 5 (Cellular), released on 2017-12-13T18:08:55Z. The update package is 501.73 MB. This is a delta (partial) update that requires 11.0.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 182eca993f2305235e53442e5bec626b5d8224ec.zip.