Hi,
If it's a Mini V1, then you can only update to the latest mini V1.
The same with Mini V2.
You need a Mini V3 to get the latest version. If it's not a Mini V3 and wan't that, then you will have to pay for an upgrade. Only Mini V3 have Arturias powerful preset browser.
I would be careful. I think it's strange if a seller can't remember or find out which version it is. It should be easy.