iOS 9.9.10.3 (build 14E5273a) is an official Apple over-the-air update for the iPhone 5s (GSM), released on 2017-03-13T17:02:01Z. The update package is 1.63 GB. This is a full OTA update that can be applied from any compatible base version. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: db60cb046aafd3d98b7fc0481510b6b6fa7a24bc.zip.