iOS 8.1.3 (build 12B466) is an official Apple over-the-air update for the iPhone 5s (GSM), released on 2015-01-27T17:55:06Z. The update package is 894.96 MB. This is a delta (partial) update that requires 7.1.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: e2aabe4830ed657938a96e71377b7ec5d1814559.zip.