iOS 9.3 (build 13E5225a) is an official Apple over-the-air update for the iPhone 5s (GSM), released on 2016-03-01T18:13:47Z. The update package is 147.12 MB. 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: 053483e14d750685cf966501abeb6f1b561435aa.zip.