iOS 12.1 (build 16B5077c) is an official Apple over-the-air update for the iPhone 6s, released on 2018-10-09T17:05:59Z. The update package is 444.76 MB. This is a delta (partial) update that requires 12.0 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 6fbc6ae51f0e815557a32cb8150fc2510154f329.zip.