iOS 12.1.3 (build 16D5032a) is an official Apple over-the-air update for the iPhone 8 Plus (GSM), released on 2018-12-19T18:06:55Z. The update package is 293.4 MB. This is a delta (partial) update that requires 12.1.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: a6ef68f4fea3aad3640ecd35cd6f4f3517728287.zip.