iOS 9.2.1 (build 13D15) is an official Apple over-the-air update for the iPhone 5 (GSM), released on 2016-01-19T17:59:42Z. The update package is 871.12 MB. This is a delta (partial) update that requires 8.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: c7255b676549e27f6f56838963f1c568d2731ffb.zip.