External authentication methods (EAM) – Public preview update

External Authentication Methods (EAM) Public Preview will enforce registration starting December 8, 2025. Existing users are pre-registered; new users after December 2, 2026, must complete in-line setup. Admins can register users. Organizations should prepare by communicating changes and reviewing configurations. Introduction We’re updating the Public Preview of External Authentication Methods (EAM) to improve security, strengthen configuration validation, and prepare for General Availability planned for the end of March 2026. Tenants currently using EAM in Public Preview should review the changes below. When this will happen Registration enforcement begins December 8, 2025. How this affects your organization Who is affected: Tenants currently using External Authentication Methods (EAM) in Public Preview. What will happen: Registration enforcement: Users must have an external authentication method registered to use EAM. In-line registration for new users: Existing users have been registered by Microsoft – which means there’s no action required. New users (any user joining your tenant after December 2, 2026) will be prompted during sign-in to complete in-line setup with your external provider. IT admins can register users on their behalf if needed. What you can do to prepare Communicate to users that starting December 8, 2025, they may be prompted to configure an external method during sign-in if they don’t already have one. Review your external authentication method configurations to ensure they meet validation requirements. Update internal documentation, training materials, and helpdesk guidance. Learn more: Microsoft Entra multifactor authentication external method provider reference (Preview) Manage an external authentication method in Microsoft Entra ID (Preview) Compliance considerations No compliance considerations identified, review as appropriate for your organization. Message ID: MC1192252

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