iOS 12.0 (build 16A366) is an official Apple over-the-air update for the iPhone 5s (GSM), released on 2018-09-12T19:10:29Z. The update package is 1.7 GB. This is a delta (partial) update that requires 10.2.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 86094c70ac138014adb33b7d1c87d06ae570d0fa.zip.