I have a single user license on the calendar class. You would need to purchase your own license from the developer. There is a developer license available that I could distribute, however I would need to sell the calendar product to pay for the developer licensing fees. I'm not sure it's a product I'd be able to sell enough copies to pay the fees and justify the ongoing product support and maintenance.
EDIT: I checked on the availability of the calendar class and it has been set to "End of Life" by the developer. I entered negotiations with him today to buy the rights to the code base, however the price was a little too steep. With the newest rendition of vb5 being php7 compatible, I figure the best course of action will be to write from scratch a php7 calendar class for the plugin. It will probably be easier considering the old class built the complete calendar html, contained it's own css and loaded it's own higher than vb version of jquery. It was challenging getting it working correctly. With a class from scratch, I can do it vb5 style keeping the php spitting out info to the templates and have the templates build the calendar.