iOS 12.0 (build 16A5308e) is an official Apple over-the-air update for the iPhone 6s, released on 2018-06-19T17:04:55Z. The update package is 1.16 GB. This is a delta (partial) update that requires 11.4.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 6dbb6655990b6162f6347844888eafb08d6eac14.zip.