iOS 12.4 (build 16G5027i) is an official Apple over-the-air update for the iPhone 6s+, released on 2019-05-20T17:07:28Z. The update package is 210.64 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: 4cb2a6a4ed926ee98dd53be83799b2810d96d2a1.zip.