From https://www.cutviewer.com/buy/
"Unfortunately, Cutviewer is no longer available for sale. Should this change in the future, we'll update this page."
CNCCookbook has one of the best as it can do macros as well
I think the devloper of Cut Viewer has passed on. I was not aware that he was responsive to bug reports, but development seemed to have been at a stop for many years.
That is very sad news. He seemed to be a very nice guy...