iOS 11.1 (build 15B93) is an official Apple over-the-air update for the iPhone 6s, released on 2017-10-23T17:07:42Z. The update package is 235.72 MB. This is a delta (partial) update that requires 11.0.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 5196cd3c867dd13efb589c2df6bc3d0b38aa2c4a.zip.