Official AMD website - for desktop only Ryzen 5000 or newer; for mobile only Ryzen 3000 or newer
The way they did the distinction is purely based on the time of put on sale. They patch Zen+ on mobile, they patch Zen2 on desktop only if it comes with integrated GPU, otherwise it needs to be zen3 or higher. If you already fixed the exploit on zen+ and Zen2 why not making available for everyone? Selling more CPUs I guess…