iOS 8.1.3 (build 12B466) is an official Apple over-the-air update for the iPhone 5 (GSM), released on 2015-01-27T17:55:05Z. The update package is 148.65 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: 3252f0bcfb37dd979ec97bdcf734b8e932603d74.zip.