iOS 12.1.3 (build 16D39) is an official Apple over-the-air update for the iPhone 6+, released on 2019-01-22T18:10:18Z. The update package is 217.1 MB. This is a delta (partial) update that requires 12.1.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: b1447c1c6d8e5978f9bdf366d55b163950cbec9f.zip.