iOS 9.1 (build 13B143) is an official Apple over-the-air update for the iPhone 6s, released on 2015-10-21T17:16:05Z. The update package is 252.06 MB. This is a delta (partial) update that requires 9.0.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 80f3e07f32984cfb535fc4156c623171a92c681f.zip.