Missing download link for Capture One 20 (wanting to upgrade my Perpetual License 12)

Hello everyone!

I'm a bit despaired, as I've tried to find a download Link for Version 20 (mac) but I wasnt successful.
Currently I'm only allowed to use my Perpetual License for Version 12  and I've used the upgrade function to V20 once in the past on a windows computer. Now I've got myself a MacBook and I wanted to use V20 on my Mac instead of my Windows computer.

So my thinking was to deactivate all active version, so I could upgrade to Version 20 again.
Not sure if this still works?

I'm happy for any recommendations and answers.

Thank you!