iOS 12.1.3 (build 16D39) is an official Apple over-the-air update for the iPhone SE, released on 2019-01-22T18:12:30Z. The update package is 217 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: c5a3d6d0126dfdb7848e74331d89e42fd49c31fe.zip.