iPadOS 12.1.3 (build 16D39) is an official Apple over-the-air update for the iPad 6 (Cellular), released on 2019-01-22T18:08:24Z. The update package is 1.27 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: c5817014158934fee072c5d236157b7dca8d757e.zip.