Microsoft Depreciating Basic Authentication on SMTP: What It Means for SAP Business One Users

On October 1st, 2025, Microsoft will officially retire Basic Authentication for SMTP Client Submission (SMTP AUTH) in Exchange Online. This change is part of Microsoft’s ongoing efforts to enhance security and protect users from credential theft, phishing, and brute force attacks. Basic Authentication, which transmits usernames and passwords in plain text, will no longer be supported, and users will need to transition to more secure authentication methods such as OAuth. 

The Impact on SAP Business One

SAP Business One, relies on SMTP for various functionalities, including the automatic sending of business documents such as invoices, purchase orders, and delivery notes. The deprecation of Basic Authentication will have significant implications for businesses using SAP Business One, particularly in the following areas:

1. Automated Email Notifications: SAP Business One uses SMTP to send automated email notifications for various business processes. With the deprecation of Basic Authentication, these automated emails will fail to send unless the system is updated to use OAuth or another supported authentication method.
2. Third-Party Add-Ons and Modules: Many businesses use third-party add-ons and modules with SAP Business One to enhance functionality. These add-ons often rely on SMTP for sending emails. The deprecation of Basic Authentication will require updates to these add-ons to ensure they support OAuth or another secure authentication method.
3. Custom Integrations: Businesses with custom integrations that use SMTP for sending emails will need to review and update their integrations to support modern authentication methods. This may involve significant development work and testing to ensure compatibility and security.

Steps to Prepare for the Change

To mitigate the impact of this change, businesses using SAP Business One should take the following steps:

1. Conduct an Assessment: Frontline will perform a comprehensive assessment of your SAP Business One environment, including any third-party add-ons and custom integrations, to identify where Basic Authentication is used. This will help determine the scope of the required changes and identify which services are at risk of failing.
2. Transition to Modern Authentication: Frontline can update your SAP Business One environment and any associated add-ons or integrations to use OAuth or another supported authentication method. This may involve working with your IT team or third-party vendors to ensure all components are updated and tested.
3. Utilise External Email Services: Consider using an external high-volume email supplier (external SMTP service) for your email needs. This can help ensure that your business documents continue to be sent without interruption while you transition to modern authentication methods.

Conclusion

The deprecation of Basic Authentication for SMTP Client Submission by Microsoft is a significant change that will impact many businesses using SAP Business One. By proactively assessing your environment, transitioning to modern authentication methods, and engaging with support services if needed, you can ensure a smooth transition and continue to benefit from the automated email functionalities that SAP Business One provides. For more information on how to prepare for this change and update your SAP Business One environment, please contact your account manager or fill out our contact form