Meanwhile, Apple stopped offering TechTool Deluxe with AppleCare subscriptions: see today’s comment of Michael Schmitt
They even removed the download page, even for users who have inforce AppleCare agreements purchased when TechTool Deluxe was part of the contract.
That last is a bit on the nasty side.
Oh, well... I guess all good things eventually come to an end (Consider how much less stuff is in the box when you buy a new Mac today as opposed to 10 years ago.), and the upgrade has always been pretty low-key and, I suspect, not overly taken advantage of, anyhow.
But anybody who's already got TT Deluxe can still avail hirself of the upgrade, although I have no idea if there's any time limit on when you have to have obtained TTD.
Aside: Since Micromat does not offer TTD as a product for sale, I guess it's extinct.