Tenant External Recipient Rate Limit (TERRL) quotas in Exchange Online will change starting mid-September 2026 for new, trial, and EDU tenants, adjusting limits based on tenant age and license type. Trial tenant quotas reduce to 500 recipients daily; EDU quotas use a new formula. Exceeding limits blocks outbound messages.
Applies to: Microsoft 365 suite
Source: mc.merill.net — data via Merill Fernando's open archive (MIT).