The update is only compatible with Honor 30 Pro EBG-AN00, Honor 30 Pro EBG-TN00 and Honor 30 Pro + EBG-AN10. It is being rolled out in China as of now via OTA (Over-the-air)  in a phase-wise manner just like any other update. So it will take some days to be available all across the globe. Meanwhile, you can manually,  you can manually check for the update. If you own the device, you can manually check for the update, Go to System > Software update > Check for updates. or open HiCare app > Update > Check for updates. If you want to know the changelog, check down below

Changelog

Camera

Optimize the camera effect in some scenes.

System

Optimize the stability of the system and make your phone run more stable.

Source

The latest Magic UI 3 1 0 138 update is now live for Honor 30 Pro and 30 Pro  - 47