Microsoft is retiring Exchange Web Services (EWS) in Exchange Online on October 1, 2026 and will no longer be available for use at that university. After that date, applications and email clients that still use EWS will no longer be able to connect to Microsoft 365 mailboxes. Learn more on Microsoft's website.

What is EWS? 

Exchange Web Services (EWS) is an older technology used by some applications to access Exchange Online services such as: 

• Email
• Calendars
• Contacts 
• Mailbox automations
• Service accounts and workflow integrations 
  

While most Microsoft 365 applications have already transitioned to modern technologies, some third-party applications, custom integrations and automated processes may still rely on EWS.

Who Is Not Impacted? 

Most Outlook users will NOT be affected. Modern versions of Microsoft Outlook and Microsoft 365 applications do not rely on EWS.

If you use any of the following, no action is needed: 

• Outlook for Windows 
  
• New Outlook for Mac 
  
• Outlook on the web 
  
• Outlook Mobile

Who Is Impacted? 

Apple Mail Users 

Apple Mail uses EWS when connected to a Microsoft 365 or Exchange Online mailbox. After EWS retirement, Apple Mail will no longer be able to access Exchange Online email, calendar, contacts or other mailbox data. 

Solution: Users should migrate to Microsoft Outlook for Mac or another supported Microsoft 365 client. 

Legacy Outlook for Mac Users 

Legacy Outlook for Mac relies on EWS connectivity and will no longer function with Exchange Online after EWS retirement. 

Solution: Users should switch to New Outlook for Mac, which uses modern Microsoft 365 technologies and does not depend on EWS. 

Other Applications and Integrations 

EWS-dependent solutions may experience service interruptions as Microsoft ends support such as: 

• Third-party applications 
  
• Room reservation integrations 
  
• Custom solutions  
  
• Mobile apps  
  
• Calendar tools  
  
• CRM integrations  
  
• Automation processes  
  

Solution: If you use an application that interacts with your Microsoft 365 mailbox, calendar, contacts or other Exchange Online services, verify with the application owner or vendor that it supports modern authentication technologies and/or Microsoft Graph.

Action Required

Apple Mail users: Transition to Outlook for Mac. 

Legacy Outlook for Mac users: Switch to New Outlook for Mac. 

Application owners: Review and update any applications, scripts, services, or integrations that use EWS. 

If you have questions about whether an application or email client uses EWS, please contact the Service Desk.