iOS 12.1.3 (build 16D39) is an official Apple over-the-air update for the iPhone 8 (GSM), released on 2019-01-22T18:09:05Z. The update package is 284 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: cbf24e2b55ffb5df91326c24bc319058b0af2793.zip.