Exchange Online was going to enforce a 2,000 external recipient rate limit within the existing 10,000 recipient limit starting April 2026 for new and trial tenants, and October 2026 for existing tenants. DoD, GCC, and GCC High were excluded. High-volume senders were to use Azure Communication Services for Email. The rollout of this limit has been cancelled.
Applies to: Exchange Online
Source: mc.merill.net — data via Merill Fernando's open archive (MIT).