Microsoft will begin retiring Exchange Web Services (EWS) in Exchange Online starting October 1, 2026. EWS is an older technology used by some email and calendar applications to connect to Microsoft 365. 

As Microsoft rolls out this change, older applications and devices that still rely on EWS may gradually lose access to Microsoft 365 email and calendar services. Impacts may begin in October 2026 and continue over the following months.

Am I Affected?

Most people using current versions of Microsoft Outlook will probably not feel any impact.

You may be impacted if you use:

• An older email or calendar application
• A device running an unsupported operating system
• A third-party mail or calendar application that has not been updated in several years
• Older synchronization tools that connect email or calendar data to another application

If you are unsure which application your device uses, review the examples below or contact your local IT support provider.

Which Email Applications Does Cornell Support?

The university supports up-to-date Microsoft Outlook clients for faculty and staff, including:

• Outlook for Windows (Microsoft 365 Apps) 
• Outlook for Mac 
• Outlook Mobile App (iOS/Android) 
• Outlook on the Web

These applications use Microsoft's current connection and security methods and are expected to continue working after EWS is retired.

What About Apple Mail, Gmail, and Other Email Apps?

Some non-Outlook email applications may continue to work, if they align with Microsoft's modern authentication methods. However, non-Outlook email applications are not supported by Information Technology at Cornell beyond best-effort.

Examples of non-Outlook clients that might continue to work include: 

• Apple Mail on a supported iPhone, iPad, or Mac 
• Gmail on a supported Android device 
• Other recently updated email applications 

For non-Outlook email and calendar applications, Cornell provides only best-effort support. If a third-party email application stops working or experiences problems, the IT support staff may recommend switching to a supported Outlook client rather than troubleshooting the third-party application.

What Devices and Applications May Be at Risk?

Any device that no longer receives updates from the manufacture is at risk for email and calendar malfunction after the EWS retirement. Devices that cannot run current software are similarly at risk.

Some of the computers and mobile devices most likely at risk include:

• Windows 7 computers 
• Windows 8 computers 
• Some unsupported Windows 10 systems 
• Macs running unsupported versions of macOS 
• Older iPhones and iPads 
• Older Android phones and tablets 
• Devices running old email or calendar applications that have not been updated in several years

These examples do not represent a complete list. Other devices or applications could be affected as Microsoft retires EWS.

Anticipate Verified Email Regarding EWS Use

Current reporting tools can reveal some of the applications still connecting to EWS for email and calendar activity. The Microsoft 365 email team in Information Technology at Cornell is trying to identify those accounts connecting to EWS, in order to send their owners a verified email about the EWS retirement.

Received an Email Notification

If you received an email notification, one or more of your applications may be using EWS. These applications are at risk of failure after Microsoft retires EWS. Review your options below.

Did not Receive an Email Notification

Not all devices and applications connecting to EWS can be identified through available reporting tools. If your device or applications match any of the at-risk criteria, review your options below.

Prepare for EWS Retirement

Modernize now to avoid email and calendar disruptions later.

As Microsoft retires Exchange Web Services, some older devices and applications may gradually lose access to Microsoft 365 email and calendar services. Reviewing and updating older hardware and software now can help prevent future issues.

• Update and keep your operating system current
• Install updates for your email and calendar applications 
• Use a supported Microsoft Outlook client whenever possible 
• Replace devices that can no longer run supported software 
• Reconnect or reauthorize applications if prompted to use Microsoft's current sign-in methods 
• Consider using Outlook on the Web if an older desktop application is no longer supported

Need Help?

If you have questions or need assistance, contact the IT Service Desk or your local IT support provider.