iPadOS 11.2.1 (build 15C153) is an official Apple over-the-air update for the iPad 5 (WiFi), released on 2017-12-13T18:08:49Z. The update package is 332.93 MB. This is a delta (partial) update that requires 11.1.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 36fb06ef16efcf69a7bcedc149eedc7454f6f950.zip.