iOS 8.4.1 (build 12H321) is an official Apple over-the-air update for the iPhone 5s (GSM), released on 2015-08-13T18:05:14Z. The update package is 494.93 MB. 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: 131cb4f22eef0740d964a8b861098b3387ffc8b1.zip.