iOS 12.3 (build 16F5129d) is an official Apple over-the-air update for the iPhone 6, released on 2019-04-08T17:05:10Z. The update package is 371.96 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: 39dde563bec5517bd1662655e1ba7800216394c7.zip.