iOS 12.1.2 (build 16C101) is an official Apple over-the-air update for the iPhone 6s+, released on 2018-12-17T21:07:10Z. The update package is 1.4 GB. This is a delta (partial) update that requires 11.2.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 4f9c0d886b924a92de2b488bd23fe0de00c31995.zip.