iPadOS 12.1.3 (build 16D5032a) is an official Apple over-the-air update for the iPad Pro (10.5-inch, Cellular), released on 2018-12-19T18:06:45Z. The update package is 222.5 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: cbce4da0ee13a19a0a92fc670db7ab8fcf491b73.zip.