Exchange Web Services enters the final stretch before Microsoft pulls access

Microsoft begins disabling Exchange Web Services (EWS) in Exchange Online today, ahead of the API's permanent retirement on April 1, 2027. Introduced with Exchange Server 2007, EWS allows applications to access mailbox data including email, calendars, and contacts. Microsoft says the service "no longer aligns with today's security, scale, or reliability requirements" and recommends moving integrations to Microsoft Graph, although some capability gaps remain. Beginning October 1, Microsoft will start changing tenant-level EwsEnabled settings left at $null to $false, blocking EWS. Administrators needing temporary continuity can explicitly set the value to $true and add approved applications to the EwsAllowedAppIDs list. Applications not on that list will be blocked. That buys time only until April 1, 2027, when Microsoft will disable EWS permanently. The company was unequivocal: "There will be no exceptions." The retirement applies only to EWS in Exchange Online. EWS in on-premises Exchange Server is unaffected. …