iOS 10.2.1 (build 14D23) is an official Apple over-the-air update for the iPhone 5s (GSM), released on 2017-01-09T17:55:55Z. The update package is 58.11 MB. This is a delta (partial) update that requires 10.2.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: f1e74f5a11998febd9bfdf73fdc1f31c1b1e4de9.zip.