iPadOS 12.3 (build 16F5155a) is an official Apple over-the-air update for the iPad mini 2 (Cellular), released on 2019-05-07T17:03:38Z. The update package is 348.2 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: 5af44da6220ad13ae1169ea6e7d33f5cd0ec97bd.zip.