Hi Imran,
Sorry, I can’t really say anything in general. It is safe to say that most of them do not work with the current release.
If something works, like the PyParametric Tools (You have had asked over there about this one), then my impression is, a few tools work, most others not.
As long as there is no update labeled as “works with R21” you’re sadly out of luck.
Sorry to have no better news for you.
My best wishes.