iOS 13.1 (build 17A5821e) is an official Apple over-the-air update for the iPhone 6s, released on 2019-08-27T17:29:25Z. The update package is 362.42 MB. This is a delta (partial) update that requires 13.0 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 1533319655177f79588cd67bc643192bec2a0f0b.zip.