iOS 9.2.1 (build 13D15) is an official Apple over-the-air update for the iPhone 5s (GSM), released on 2016-01-19T17:59:50Z. The update package is 36.9 MB. This is a delta (partial) update that requires 9.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 2631910f517dd2dcfcca5c096116fbf8f7f3f01a.zip.