iOS 13.1 (build 17A5837a) is an official Apple over-the-air update for the iPhone 6s+, released on 2019-09-10T20:27:10Z. The update package is 318.3 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: 85a39aa87059fbb68064c0158a7d2f0a63ae835a.zip.