Right now we don't have a features comparison page. However, all features described in the product presentation page
are available in the Professional release. You may also want to check the documentation for details on the features, but I think you already did that.
Regarding your other question, you would need to upgrade to the Deluxe subscription level. If you log in to our site and click on Subscribe, DELUXE you will see that there is an automatic discount being applied which depends on the remaining time in each of your current subscriptions. This is determined automatically, by our software, based on a complex mathematical formula. So the easiest way to see your upgrade price is going to that page.
Nicholas K. Dionysopoulos
Lead Developer and Director
🇬🇷Greek: native 🇬🇧English: excellent 🇫🇷French: basic • 🕐 My time zone is Europe / Athens
Please keep in mind my timezone and cultural differences when reading my replies. Thank you!