Smush Pro functions as regular Smush

I installed WP Smush first to try it out and liked it. I removed the standard Smush and downloaded/installed the Pro version.
In my modules list it shows as Pro, but the interface shows as standard with all pro version features greyed out. Is there anything special I need to do to activate the pro-version?
I do not have wpmu dashboard installed for the site - is that a requirement? I would prefer not to in this instance.