Thank you for the reply, Srek, I'm just asking for a simple compatibility information, not for extending functionality. Most software I am working with have such an indication of backwards compatibility somewhere in their product description. It may come with a caveat formula, but it would be helpful. While I'm searching for this information, I've found several contradictory statements in different forums about if R21 is working or not with Big Sur. I would love to see some official information about this before investing time and money into hardware and software upgrades.
In my life experience, a company (in the software area but also in general) which has an approach to care about existent and longterm customers and not only about their future and potential ones has a much better chance to keep a large user base. if you get the feeling as a customer that the company cares about existant users and doesn't just push (even indirectly) every time for upgrades, you will much more likely stick to the product and follow it's upgrade path when finally needed - simply because you will perceive the product as part of your reliable working environment and not an expensive to maintain tool. Such a perception would contribute to switch over to another more competitive product. Just my 2 eurocents.