Microsoft details how to re-enable Exchange Online EWS for apps broken by the default block
Microsoft says Exchange Online administrators can temporarily re-enable the retired Exchange Web Services (EWS) API to restore apps that stopped working after the default block began on October 1, 2026. EWS is used by Outlook desktop add-ins, older Outlook for Windows versions, Apple Mail/Calendar on macOS and other apps. When EWS is disa…