Outbound email: Migration to modern Microsoft 365 authentication (OAuth)
This release replaces legacy username/password SMTP authentication with Microsoft’s OAuth authorization code flow when integrating outbound email with Microsoft 365. The new method eliminates the need to store user credentials and aligns with Microsoft’s planned deprecation of basic authentication, improving security and long-term compatibility.
When configuring outbound email using OAuth, administrators only need to provide the Application ID, Directory ID and Client Secret. Existing configurations using the legacy method will continue to function temporarily, but administrators will see a persistent banner prompting them to migrate. The banner will also notify admins if an issue occurs when refreshing the SMTP OAuth access token.
Important: Migration should be completed before Microsoft begins deprecating basic authentication — currently expected to start December 31, 2026 — to ensure uninterrupted outbound email functionality.
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