iOS 12.1.3 (build 16D39) is an official Apple over-the-air update for the iPhone 8 (Global), released on 2019-01-22T18:08:33Z. The update package is 1.44 GB. This is a delta (partial) update that requires 11.4.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 78ee63d01a8ef9f3f4d4e09bd64ed4a20459355a.zip.