iOS 9.1 (build 13B137) is an official Apple over-the-air update for the iPhone 5s (GSM), released on 2015-10-12T16:56:56Z. The update package is 1.33 GB. This is a delta (partial) update that requires 9.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 4bead7239e6d57d47e4ec7e4799c96b94e265fe0.zip.