Microsoft Ends SMS MFA — 2027 Deadline

Key insights

• Passkeys become the default sign-in experience on September 1, 2026, and Microsoft will fully retire its native SMS and voice MFA delivery on February 1, 2027.
  Plan migrations early so users are ready before the enforced retirement date.
• Microsoft is moving tenants to phishing-resistant methods such as passkeys, Windows Hello, and FIDO2 because SMS and voice codes are easier to attack.
  This is a shift in delivery, not a removal of multi-factor authentication itself.
• After the cutoff, any user whose only method is SMS or voice will see a blocking prompt that requires registering a passkey before they can continue signing in.
  There is no broad opt-out for the February enforcement.
• Organizations that still need telephony-based MFA must adopt a customer-managed telecom provider through the Microsoft Security Store—Microsoft’s built-in delivery will no longer be available after the retirement date.
  Start procurement and testing early if you have regulatory or business needs for phone delivery.
• Admin checklist: inventory users still on SMS/voice, enable passkeys and other phishing-resistant options, decide on synced vs device-bound passkeys and require attestation, and run a registration campaign to move users at scale.
  Communicate changes to reduce help-desk load and prevent sign-in interruptions.
• Key transition milestones to track: August 1, 2026 (temporary API opt-out available), September 18, 2026 (telecom provider details published), October 30, 2026 (configure a telecom provider), and February 1, 2027 (full retirement).
  Use PowerShell or Graph API options now to control the September auto-rollout if needed, and finish migrations before February.

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