This is exactly what I needed to know. Thanks!

(1) It seems like the kind of thing I should have been able to find via search. Could be that I had an unfortunate mix of search terms, but I'm guessing others might fall into a similar trap. I purchased Multiplicity via Steam, and the three types of licenses were not mentioned, there.

(2) In light of this, perhaps the error message in my original post should say something like, "A KVM Pro license is required to add more than one connection, here."

Thanks!

Hello,
I have forward your problem/question to Stardock Support Team for their assistance. Please keep an eye on this thread for any updates. We appreciate your feedback and patience.

Basj,
Stardock Community Assistant

I have figured this out, and honestly, I'm "impressed." I use quotes here because you guys are doing something that shouldn't be earth-shattering, but if you buy licenses of things on Steam, it is amazing how some companies seem completely oblivious of the transaction. When I went to upgrade Multiplicity, your store gave me a discount based on the active Steam subscriptions! While it may have taken me a bit to find what I was looking for, once you told me where it was, the process was super-easy and intuitive. Shame to those companies who don't consider their Steam customers as "customers."

That said, the exact dialog in my original post could use a better error message to guide folks to the right place. And probably something in the "about box" should alert the customer that "The Pro Version of this software is not available from Steam."

My day job is with ServiceNow, so I'm all about "deflecting" that next customer service contact.