Sad to read the announcement at the top of the page, but inevitable I guess, given that Windows 7 is now end-of-life.
Many thanks to Mark for making such a great add-on, for the fixes when TheTVDB API went bad, and for kindly allowing the installer and key to be freely distributed.

It would be awesome if the source code could be released so that RTVHD can live on beyond the site closure.