iOS 12.1 (build 16B5068i) is an official Apple over-the-air update for the iPhone 6s, released on 2018-10-02T17:12:04Z. The update package is 440.71 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: 3d1eb3a5de07912281a22c5784693f24b0d757fb.zip.