Unfortunately there is an upgrade price. For the basic upgrade from any previous versions of Ozone to upgrage to Ozone 6 costs $99. Its hard to say at this stage what you are going to get for your $99. Izotope state this which does not tell you much:-
“Ozone 6, the latest version of iZotope’s complete mastering system, has a workflow centered around creativity: A redesigned, modern interface guides and inspires users of all experience levels at every step, so you can freely experiment with ease”.
I was more interested in this statement from them: “Reinvent timeless sounds by harnessing the sonic texture of classic analog gear, then tweak with the surgical precision of digital software. An intuitive display and robust visual feedback let you dial in your signature sound in just a few clicks”.
This is a “Coming Soon” clip to get you interested:-