iOS 12.1 (build 16B92) is an official Apple over-the-air update for the iPhone 6, released on 2018-10-30T17:16:52Z. The update package is 1.35 GB. This is a delta (partial) update that requires 11.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 4c5eac050dbe86fcb46886c3528d21a02ec804a4.zip.