iOS 12.0 (build 16A366) is an official Apple over-the-air update for the iPhone 6s+, released on 2018-09-12T19:11:56Z. The update package is 1.34 GB. This is a delta (partial) update that requires 11.3.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 6e62241fe681d2ef96b1e6ff9d486a7cc08d6bd9.zip.