Microsoft Warns Entra ID Admins to Replace SMS Authentication Before February 2027

Microsoft is reminding Entra ID administrators to migrate users away from SMS and voice authentication before February 1, 2027, when the company will begin retiring its native telecom authentication service.

According to Microsoft 365 Message Center advisory MC1528000, organizations that fail to prepare could face user sign-in disruptions.

The company recommends passkeys and other phishing-resistant authentication methods to reduce security risks associated with phishing and SIM-swap attacks.

Microsoft is retiring native SMS and voice authentication

Starting February 1, 2027, Microsoft will begin retiring its own SMS and voice authentication delivery service for Microsoft Entra ID workforce tenants.

The change will not affect Azure AD B2C or Microsoft Entra External ID customer identity scenarios.

Organizations can replace SMS and voice authentication with passkeys, FIDO2 security keys, QR code authentication, or other supported Entra ID authentication methods.

However, Microsoft is not eliminating SMS and voice authentication entirely. Organizations that still need these methods can configure a customer-managed telecom provider (CYOT) through the Microsoft Security Store.

Microsoft previously introduced the option to use third-party telephony providers to help organizations prepare for the transition.

Administrators need to identify affected users

Microsoft advises Entra ID administrators to review their existing authentication policies and identify users who still depend on SMS or voice verification.

To simplify the process, administrators can use Microsoft’s Entra SMS/Voice Policy Scanner PowerShell script to identify affected users and configurations.

Organizations should complete their migration before February 2027 to avoid authentication failures when Microsoft begins retiring its telecom service.

Microsoft has previously urged Entra ID customers to move from SMS authentication to passkeys, making this latest reminder another warning ahead of the deadline.

Passkeys are becoming the default authentication method

In July 2026, Microsoft announced plans to make passkeys the default authentication experience for Entra ID users, with the rollout beginning in September.

As the rollout reaches organizations, users who currently have SMS or voice authentication enabled will automatically become eligible for passkeys.

During their next multifactor authentication attempt, these users will receive a prompt to register a passkey.

The transition aims to reduce reliance on authentication methods vulnerable to phishing, interception, and SIM-swap attacks.

In other Entra ID news, Microsoft recently removed custom CSS layout options from Entra ID as part of its efforts to combat phishing attacks.

Via BleepingComputer