iOS 12.3 (build 16F5148a) is an official Apple over-the-air update for the iPhone 6s, released on 2019-04-29T17:36:13Z. The update package is 90.79 MB. This is a delta (partial) update that requires 12.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: edb4cb73b41887f47e136c5303bb257b20d92cd6.zip.