iPadOS 12.3 (build 16F5117h) is an official Apple over-the-air update for the iPad Pro 3 (12.9-inch, Cellular), released on 2019-03-27T17:06:16Z. The update package is 334.14 MB. This is a delta (partial) update that requires 12.2 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 44140b6a2937563476044f25e2b63a1e4a817acf.zip.