upgrade from 3.4 to 4.0

[lidija]

I want to buy a site from a guy that use Vivvo 3.4.
If I buy Vivvo 4.0 is there a problem to upgrade from 3.4 to 4.0?

[Alex]

Hardly... You need to upgrade from 3.4 to 3.5, and then install 4.0 and import database from 3.5 inside. Which leaves the problem of custom template design.

On the other note, are you sure the person who is trying to sell you Vivvo 3.4 website has a legal license?