Microsoft Outlook for iOS/Android will soon warn users when emailing a large number of recipients, with the default threshold set at 25 people. The rollout starts in early May 2025 and completes by early July 2025. Admins can customize the large audience size. No admin action is required.
Applies to: Exchange Online · Microsoft 365 apps
Source: mc.merill.net — data via Merill Fernando's open archive (MIT).