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 30.84 MB. This is a delta (partial) update that requires 9.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: eff9f99e0c7e119fbb1fc4709265579d2c96dd16.zip.