Exchange Online will permanently remove support for Basic authentication with Client Submission (SMTP AUTH) in September 2025. After this time, applications and devices will no longer be able to use Basic auth as an authentication method and must use OAuth when using SMTP AUTH to send email.

This will impact Sage CRM but we know about this and in our work to modernise the Sage CRM features have already implement integrations based on Microsoft Graph.

This is just a refresh to let people know that though the end for Basic Auth is nearer Sage has confirmed support for OAuth 2.0 since Sage CRM 2020 R2.

https://communityhub.sage.com/sage-global-solutions/sage-crm/f/sage-crm-announcements-news-and-alerts/153882/advisory-enabling-exchange-integration-to-use-oauth-2-0-modern-authentication-when-connecting-to-exchange-365-exchange-online

Support for OAuth 2.0 (Modern Authentication) to support specific features has been added to the following versions of Sage CRM.

• Exchange Integration (Sage CRM 2020 R2 onwards)
• Internal Mail Client (Sage CRM 2021 R1 onwards)
• Advanced Email Manager (Sage CRM 2021 R1 onwards)
• Import of Contacts and Emails (Sage CRM 2022 R2 onwards)

Note:  Support for Sage CRM 2021 R1 and R2 will end on 30th September 2024. (Supported Sage CRM versions | Sage CRM Help Center) 

Here is the initial Advisory from Sage 2 years ago with FAQs at the bottom that are still relevant. 

https://communityhub.sage.com/sage-global-solutions/sage-crm/f/announcements/190313/advisory-impact-of-end-of-support-for-basic-authentication-for-integration-with-microsoft-exchange-online?irclickid=3pJzbmw7pxyKRyCRXmy74WpRUkC1yFUeDT8a0E0&utm_source=affiliate&utm_medium=leadgensage&utm_campaign=ImpactAffiliateProgramme&utm_content=123201&sharedid=231384&irpid=123201&utm_term=3pJzbmw7pxyKRyCRXmy74WpRUkC1yFUeDT8a0E0_231384&irgwc=1&