If you use WorkAdventure with the freemium plan, you cannot exceed 15 simultaneously connected users in your virtual space(s).
If you upgrade to the premium plans, there is NO limit of simultaneously users. You just need to define the capacity of users you would need in your virtual space(s) and subscribe to the best plan.
WorkAdventure has already organized talks with 500+ simultaneously connected users in a conference room. We also already organized events with 10,000+ users over few days.