iOS 10.2.1 (build 14D27) is an official Apple over-the-air update for the iPhone 5s (GSM), released on 2017-01-23T18:08:14Z. The update package is 1.07 GB. This is a delta (partial) update that requires 9.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 66bfcad2b1307aeca54f8561e8c9a8bd154d8dca.zip.