iOS 12.1.1 (build 16C50) is an official Apple over-the-air update for the iPhone 6s+, released on 2018-12-05T18:10:57Z. The update package is 1.83 GB. This is a delta (partial) update that requires 10.3.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 9f1f407c3d1fd544a07b880da9725eb2682f4527.zip.