Using Classic Outlook on Windows for personal email, calendar, and contact management
Hi Debra,
Just a couple of posts up I added the following which can hopefully help answer your question. Microsoft made changes to the number so it has increased from 250 to 1,000 for scheduled meetings. So for your scenario (300-400 participants), as long as you configure it as a scheduled meeting and invite people (Outlook or MS Teams Calendar) then you will be more than fine.
Scheduled Meetings/Webinars (Outlook/Teams calendar):
- 1,000 participants
- 20,000 View/Listen only participants
https://docs.microsoft.com/en-us/microsoftteams/limits-specifications-teams
See also the introduction text which mentions the same 1,000 limit:
For reference Live events cater for higher volume:
LIVE Events
- Audience size - 10,000
- Event duration 4 hours
- 15 concurrent live events per tenant
NOTE:
until June 30 2021, Microsoft have temporarily increased this to:
Audience - 20,000
50 events per tenant
Event duration 16 hours