iOS 9.9.10.2.1 (build 14D27) is an official Apple over-the-air update for the iPhone 5s (GSM), released on 2017-01-23T18:08:11Z. The update package is 1.38 GB. This is a delta (partial) update that requires 8.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 4ab9c4071d5ce242a01ff4af023f20cee73cd455.zip.