iOS 8.4.1 (build 12H321) is an official Apple over-the-air update for the iPhone 5 (Global), released on 2015-08-13T18:05:13Z. The update package is 420.2 MB. This is a delta (partial) update that requires 8.0.1 already installed. This update is currently signed by Apple, so it can be applied from Settings › General › Software Update.

Payload file: cac1082cfb23975db7dcebc2150c1bd8cb12f555.zip.