External authentication methods (EAM) – Public preview update
From Microsoft 365 Message Center Archive by Merill Fernando · Microsoft may not have sent this notice to your tenant.Rollout
Rollout dates are often only in the text. When Microsoft moves them, the change shows under "What changed".
Schedule dates changed in the text
Date phrases in schedule sentences differ between the versions this installation saw- Seen 12 Dec 2025
December 2, 2026→ December 2, 2025
Read from date phrases in Microsoft's text, not from notice metadata. A changed phrase can be a moved rollout, a new milestone or just rewording; "What changed" below shows which.
What the notice says
Microsoft’s text, safely structuredIntroduction
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:
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:
Compliance considerations
No compliance considerations identified, review as appropriate for your organization.
What changed
Between archive captures, newest first… action required. New users (any user joining your tenant after December 2,
2026)2025) will be prompted during sign-in to complete in-line setup with your external …- · first version seen
Learn more
Links from the notice and their documentation checksRelated public evidence
- Public source · 26 Oct 2026MC1450133: Microsoft Entra: Users can register a passkey or passwordless sign-in as their first multifactor authentication method Microsoft 365 Message Center Archive by Merill Fernando
- Official documentation · 13 Oct 2026Combined security information registration
- Public source · 13 Oct 2026MC1450134: (Updated) Microsoft Entra: Windows Hello for Business and macOS Platform SSO as standalone MFA factors Microsoft 365 Message Center Archive by Merill Fernando
- Official documentation · 12 Oct 2026Authentication registration campaigns
- Official documentation · 12 Oct 2026Conditional Access authentication strengths for guests
- Official documentation · 12 Oct 2026MFA NPS extension
Not confirmed here
What this page cannot tell you- Whether your tenant is affected: this is Microsoft's notice, not a check of your settings.
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