iOS 10.3.1 (build 14E304) is an official Apple over-the-air update for the iPhone 5s (GSM), released on 2017-04-03T17:00:28Z. The update package is 744.24 MB. This is a delta (partial) update that requires 10.0.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: ecb03a16a9be2c60425397b575f97f095c06b390.zip.