iOS 6.1.3 (build 10B329) is an official Apple over-the-air update for the iPhone 4s, released on 2013-09-18T17:56:17Z. The update package is 910.27 MB. This is a delta (partial) update that requires 5.0.1 already installed. This update is currently signed by Apple, so it can be applied from Settings › General › Software Update.

Payload file: 82b056c7a9e455ad4f00d1b5169e5b56ab8c2cc7.zip.