I purchased the Desktop Plus a long time ago (2008). I still have the email with the serial # and download link.
The download link is no longer valid, and the only links I can find on Tivo's site require me to purchase it again. There's no updates (like the 2.8.3 patch) that I can find downloadable.
Is there even a support website for downloading the updates? Since it requires a serial # to function, I don't know why Tivo doesn't have it on their website as downloadable without having to re-purchase from the Tivo Store.
Their support page:
has a link to:
which isn't valid anymore and instead takes you to: