iOS 12.3 (build 16F5148a) is an official Apple over-the-air update for the iPhone 6s+, released on 2019-04-29T17:36:14Z. The update package is 91.83 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: 64029699f8132d33399a183ac903d0c4b44cf33e.zip.