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 404.81 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: 1c3fae83b34e8373b4310cdcce1a8d27b8279c5c.zip.