NewMicrosoft Teams
Microsoft Teams: Breakout rooms up to 1,000 Attendees in Teams meetings
Breakout room capability in Teams meetings is now expanded to support meetings with up to 1,000 attendees, enabling organizers to create smaller group discussions and improve engagement at scale without requiring administrator configuration.
Microsoft's description
Organizers can now use breakout rooms in Teams meetings with up to 1,000 attendees, enabling more interactive sessions, smaller group discussions, and improved audience engagement without compromising scale or performance.