iOS 12.3 (build 16F5139e) is an official Apple over-the-air update for the iPhone 6s, released on 2019-04-22T17:08:59Z. The update package is 302.43 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: fa8434496e17b7a661a76aa233e2534122b36942.zip.