iOS 9.2.1 (build 13D15) is an official Apple over-the-air update for the iPhone 5s (GSM), released on 2016-01-19T17:59:49Z. The update package is 1022.93 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: ec8c4fa07e3d3ce4a572c246e6efb414e66cfba5.zip.