IT Admin Change Calendar Microsoft 365
Exchange Web Services (EWS) starts being disabled in Exchange Online
Microsoft starts disabling EWS in Exchange Online in October 2026, with full shutdown in April 2027. Migrate EWS apps to Microsoft Graph.
Product
Exchange Online
Announced
19 September 2023
Effective from
1 October 2026
Who is affected
Organizations running applications or third-party integrations that access Exchange Online mailboxes through EWS. Exchange Server on-premises is not affected.
Admin roles to involve: Exchange admin, Microsoft 365 admin, Application owners
What administrators should do
Use the EWS Usage Reports in the Microsoft 365 admin center to find applications still calling EWS, then migrate them to Microsoft Graph. Work with vendors of third-party tools (backup, archiving, CRM, migration) that still depend on EWS. Disablement is phased from October 2026 and admin-controllable until EWS is fully disabled in April 2027.
What happens if this is ignored
EWS requests to Exchange Online start being blocked, so unmigrated integrations (backup, archiving, CRM connectors, custom apps) stop working.
Official source
Deprecation of Exchange Web Services in Exchange Online
Published by Microsoft · Source dated 1 April 2025 · Checked 24 August 2026
Last verified 24 August 2026