Customizable Tenant-level Recipient Limits

JeanNoel sorry for not seeing this sooner. No, it's not applicable to meeting invites - the calendar team chose to hard code the limit for meeting invites at a much higher limit (2.5k for multitenant, 5k for dedicated). At least one of the reasons for that is because if you send out invites to a large DL (e.g. 2k members) that DL gets counted as 1 recipient. But when the recipients ack the invite it adds them to the list of recipients in the originator's meeting. Now if the originator updates the meeting in some way (e.g. changes the date) it will send the message to all recipients (both the DL and the individual recipients who ack'd) and if the recipient count is > than the max for the sender/mailbox then it'd fail to send the update. So having a separate global upper limit for invites was how the Calendar team chose to reduce the chance of that happening for customers. 

Hope this helps and again apologies for the delay!