iOS 12.3 (build 16F5117h) is an official Apple over-the-air update for the iPhone 6s, released on 2019-03-27T17:06:26Z. The update package is 323.7 MB. This is a delta (partial) update that requires 12.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 870ef91452931da407ac4082add5dbf0acd6c517.zip.