Join button will require HTTPS meeting links

What and Why: We're updating the Join button experience in Outlook to use HTTPS meeting join URLs. Beginning the week of November 30, 2026, the Join button will no longer appear for meetings that contain only an HTTP join URL. Rollout Schedule: General Availability (Worldwide, GCC, GCC High, DoD): We will begin rolling out in late November 2026 and expect to complete by late December 2026. Impact on Your Organization: Meetings with HTTPS join URLs will continue to display the Join button. Organizations using online meeting providers, add-ins, or custom integrations that generate HTTP-only join URLs may find that the button no longer appears for those meetings. Most organizations are not expected to be affected. Action Required/Recommendations: No action is needed if your meeting providers and integrations already generate HTTPS join URLs. If you use third-party online meeting providers, add-ins, or custom integrations, confirm that they generate HTTPS join URLs. Work with the provider or integration owner to update HTTP URLs and validate newly created meeting invitations before the change takes effect. Compliance considerations: No compliance considerations identified. Review as appropriate for your organization.