iOS 12.1.1 (build 16C50) is an official Apple over-the-air update for the iPhone 6s, released on 2018-12-05T18:10:54Z. The update package is 399.29 MB. This is a delta (partial) update that requires 12.0.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 78ffc199f52cbe1582fbb53a90b2d23200d3f38d.zip.