iOS 13.1 (build 17A5837a) is an official Apple over-the-air update for the iPhone 6s, released on 2019-09-10T20:26:06Z. The update package is 317.27 MB. This is a delta (partial) update that requires 13.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 5f8b0f2f09a3ef3625f8a10d48a3d3f8d9562f44.zip.