iOS 12.1 (build 16B5059d) is an official Apple over-the-air update for the iPhone 6s+, released on 2018-09-18T17:20:24Z. The update package is 429.62 MB. This is a delta (partial) update that requires 12.0 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 404f0a301bc58d113dbbd25788cd042e017151c8.zip.