Hosting a meeting with over 100 attendees

I recently upgraded my zoom account to Zoom One business. I am hosting a webinar on zoom Monday and Tuesday.  The links were created before I upgraded. I have over 100 people attending each session. I want to ensure that the upgrade is applied to previously created meetings (prior to the upgrade) and that all of those attendees will not have an issue getting in!

Do I have to do anything to ensure that the 100 people can join the meeting. 

I am usuing just a regular zoom meeting.  Should I do a webinar instead?