iOS 12.1.3 (build 16D39) is an official Apple over-the-air update for the iPhone 7 (GSM), released on 2019-01-22T18:14:20Z. The update package is 1.43 GB. This is a delta (partial) update that requires 11.3.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 18cf1d62b9223632b7e372caefd92d9033543924.zip.