AMD has officially announced Zen3 architecture Ryzen 5000 series processors on October 8th. The latest Zen3 processors have significant performance improvements compared to the previous 7nm Ryzen 3000 series processors. For the upcoming processors, MSI has released the latest AGESA COMBO PI V2 18.104.22.168 for all X570 and B550 series motherboards (Link) to perfectly utilize the PCI-E 4.0 performance.
In response to the upgrade demands, AMD also mentioned the BIOS update for selected 400 series motherboards to support Ryzen 5000 series processors will be ready in January 2021. To respond to our users' anticipation, MSI is announcing that all 400 series motherboards, including X470 and B450, MAX, or non-MAX products, will provide BIOS updates later on that can support Ryzen 5000 processors. All the evaluation is in progress under the R&D team. A detailed BIOS release schedule will be announced after the BIOS code is provided by AMD. Please stay tuned for the latest information on msi.com.
Regarding the 300 series motherboards, including X370, B350, and A320 chips, AMD's current official information points out that they are not supported. If AMD makes any official updates later, MSI will also provide the latest information on time.