Summary
Outlook Mobile will display a banner warning when external attendees are added to meetings, rolling out worldwide from late October to late November 2026. This helps prevent accidental sharing with external recipients. No action or compliance changes are required.
Message ID: MC1515932
Published: Oct 19, 2026
Service: Exchange Online
Tag: New feature, User impact
Microsoft Message
When you add an attendee outside your organization to a meeting, Outlook will display a banner warning you that external recipients are included.
Rollout Schedule
General Availability (Worldwide): We will begin rolling out on late October 2026 and expect to complete by late November 2026.
Impact on Your Organization
Helps users avoid accidentally inviting external attendees to meetings by clearly identifying recipients outside their organization, reducing the risk of unintentionally sharing sensitive information.
Action Required/Recommendations
No action is required
Compliance considerations
No compliance considerations identified. Review as appropriate for your organization.