AMD has released the full specifications and details of the A520 chipset, which will be using the AM4 socket. The company has also mentioned that it will be compatible with the Zen 3 architecture going forward, as well as with current Ryzen 3000 desktop APUs. It can also use PCIe 3.0 lanes and supports 5 USB 3.2 Gen 2 ports.
https://www.notebookcheck.net/AMD-launches-the-A520-chipset-confirming-its-Ryzen-4000-compatibility-in-the-process.488545.0.html