Update from Cubase 7.5

I have cubase 7.5
If I want cubase 12 do I need to upgrade or update?
What happens after the purchase? Do I get a link to the update?
Will I continue to use the dongle I have today?

You can upgrade directly from your version to 12. You can also keep your current version working if you need to using the dongle you have. Go to the steinberg main page and buy Cubase and you will see the upgrade options.

You will have to get the download manager and please check out all the documentation regarding upgrades before you do anything as it’s quite a bit different than it was for your version

If the eLicenser Control Center software says that you have a “Cubase 7.5” license, please pick this option:

You’ll be sent a Download Access Code for use with the Steinberg Download Assistant.

I still don’t quite understand what I should do.
I went to the website and there are two options
Upgrade and update
It says there that for cubase 7.5 I can update and not upgrade
Is this true because the update is cheaper?
my second question is what happens after the purchase

You can only update, don’t worry.

Thank you very much