iPadOS 12.4 (build 16G5046d) is an official Apple over-the-air update for the iPad Air (China), released on 2019-06-11T17:06:57Z. The update package is 200.16 MB. This is a delta (partial) update that requires 12.4 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: c4d33c5836d2e7fc0b9dc1d7d8af0dfd243236a0.zip.