Hi Edgar,
Sorry for any confusion.
Event Tickets Plus essentially replaces WooCommerce Tickets (and our other ecommerce plugin-specific ticketing plugins). We spent a lot of time on the backwards compatibility angle of Event Tickets Plus so the transition should be a smooth one.
What I’d recommend is switching to ET+ and removing WooCommerce Tickets at your earliest convenience (due to its imminent retirement it shortly will be no longer possible to renew, upgrade or even purchase WooCommerce Tickets in any case).
Does that clarify things?