iOS 10.2.1 (build 14D27) is an official Apple over-the-air update for the iPhone 5s (GSM), released on 2017-01-23T18:08:17Z. The update package is 310.18 MB. This is a delta (partial) update that requires 10.1.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 02c0cd601d0aa0d27f30e1e2a2c6c56e84efcf8f.zip.