Event Tickets Plus is an add-on for Event Tickets, which is just another fancy way of saying that adds features to Event Tickets and that both plugins need to be activated in order for Event Tickets Plus to do its thing of helping you sell paid tickets on your site.
A perfect example of this is the ticket creation process in the post editor. When Event Tickets is activated on it’s own, there is only a single option to select RSVP as the type of ticket you are creating.
Event Tickets Plus changes this interface by adding additional ticket options, based on which ecommerce plugins are installed on your site. Event Tickets Plus integrates with WooCommerce, Easy Digital Downloads, Shopp and WP eCommerce so, depending on which of those you have installed and activated, Event Tickets Plus will display those options alongside the RSVP option provided by Event Tickets.
This extension allows you to selectively choose which ticket options should be displayed in the ticket editor. For example, you may never need RSVPs and would prefer to never display that option. Or perhaps you have multiple e-commerce plugins installed on your site, but only want to use one of them for ticket sales. Either way, this extension gives you that choice in the Events > Settings > Tickets screen.
Please note: This extension requires PHP 5.3 or newer. Future versions of Event Tickets may be able to support this with older PHP versions, but for now you must be running at least PHP 5.3.