iOS 12.3 (build 16F5155a) is an official Apple over-the-air update for the iPhone 6s, released on 2019-05-07T17:04:25Z. The update package is 64.79 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: d2c17e8638e592938cd0d68c0bfbdd89bf50a932.zip.