iOS 12.1 (build 16B92) is an official Apple over-the-air update for the iPhone 6+, released on 2018-10-30T17:16:48Z. The update package is 1.34 GB. This is a delta (partial) update that requires 11.4 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: cb882e38cf04841026d6ac7b2fde2fe65faab508.zip.