iPadOS 12.3 (build 16F5117h) is an official Apple over-the-air update for the iPad Air 2 (WiFi), released on 2019-03-27T17:05:53Z. The update package is 311.7 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: 546af898c7ba0324cefcfe891707630a967f8534.zip.