iOS 13.1 (build 17A5844a) is an official Apple over-the-air update for the iPhone 6s, released on 2019-09-18T17:07:01Z. The update package is 218.95 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: 05f5ad2a3a1f31e2248300c696bad4f861539629.zip.