Exchange Web Services (EWS) phased disablement begins in Exchange Online

Exchange OnlineMicrosoft 365

Who is affected

Any application, script, add-in or device that reads or writes Exchange Online mailboxes through EWS, including third-party backup, archiving, CRM and room-booking tools.

What to do

1. Run the EWS usage reports in the Microsoft 365 admin center to find apps still calling EWS.
2. Ask each vendor for its Microsoft Graph release and date; migrate in-house code to Graph.
3. Record apps with no Graph path yet and plan an alternative before April 2027.

Source

“Phased disablement begins October 1, 2026, with permanent retirement on April 1, 2027.”

EWS deprecation timeline“October 2026: EWS starts to be disabled globally for all organizations.”

Checked 9 Nov 2026 Link to this deadline