https://wccftech.com/amd-ryzen-3000-valhalla-cpus-x370-x470-motherboard-bios-support/

It looks like motherboard manufacturers have started adding early support on their X370 and X470 series products for the upcoming AMD Ryzen 3000 series processors. The Zen 2 based AMD Ryzen 3000 series processors are scheduled to launch in mid of 2019 and would be bringing faster clocks, higher core count and improved efficiency while utilizing the brand new 7nm process technology.

There are a few manufacturers who have started adding support for the upcoming processors in their existing products. This is part of the commitment which AMD made that all Ryzen series will be compatible with existing AM4 motherboards to offer longevity for the mainstream platforms.