AMD Mantle Version
Not Available
AMD Mantle API Version
Not Available
↑from my Radeon RX Vega with 18.10.2 driver
Mantle has passed away and Mantle has become part of DX12/vulkan.
Also about the Relive
Regarding Relive's question, I think it should be supported.
You can try to contact Acer and AMD to ask them about the specifics of the matter.
Maybe you can try to download the driver from AMD?
(I didn't use Ryzen APU + dGPU notebook,
The recommendation to download the graphics driver from AMD is for reference only)