Microsoft has officially confirmed that Exchange Web Services (EWS) will be fully shut down in Exchange Online on April 1, 2027, marking the end of nearly two decades of service. The company will begin disabling EWS by default for cloud tenants starting October 1, 2026, using a phased and admin-controlled rollout.
The change affects only Microsoft 365 and Exchange Online. On-premises Exchange Server deployments will continue to support EWS with no announced retirement timeline.
Why Microsoft Is Retiring Exchange Web Services
Microsoft says EWS no longer meets modern requirements for security, scalability, and reliability. Built almost 20 years ago, the API has already stopped receiving new features, while its replacement—Microsoft Graph—has reached near-complete feature parity for most workloads.
Microsoft has also migrated its own internal services away from EWS, and many third-party vendors have already completed or started their transitions. Retiring EWS reduces legacy attack surfaces and simplifies the Exchange Online platform.
Key Dates Administrators Must Know
Microsoft outlined a clear retirement timeline that spans late 2026 through early 2027:
- Now – August 2026: EWS remains available. Admins should review usage and begin migrating applications to Microsoft Graph.
- End of August 2026: Tenants that configure an application allow list and set
EWSEnabled=Trueavoid automatic blocking. - September 2026: Microsoft will auto-populate allow lists for tenants that did not create their own, based on observed usage.
- October 1, 2026: EWS becomes blocked by default in Exchange Online unless explicitly allowed.
- April 1, 2027: EWS shuts down permanently. Microsoft will remove all admin controls, with no extensions or exceptions.
How Microsoft Will Disable Exchange Web Services in Exchange Online
Microsoft will disable EWS tenant-by-tenant using the EWSEnabled property, which supports three states:
- True: EWS allowed only for apps on an admin-defined allow list
- False: EWS fully blocked
- Null (current default): EWS allowed until October 2026
Any tenant that leaves EWSEnabled set to Null will automatically switch to False during the October 2026 rollout, blocking all EWS access. Admins who still depend on EWS can temporarily re-enable it, but Microsoft warns this may cause service interruptions.
Microsoft Official Recommendation: Move to Microsoft Graph
Microsoft strongly recommends migrating all EWS-based applications to Microsoft Graph, which now supports most email, calendar, and contact scenarios previously handled by EWS.
For organizations unsure where to start, Microsoft advises:
- Reviewing EWS usage reports in the Microsoft 365 admin center
- Identifying apps and workflows that still rely on EWS
- Migrating high-impact or critical apps first
- Testing ahead of the October 2026 blocking phase
Microsoft will also run short, temporary EWS shutdowns—known as “scream tests”—to help expose hidden dependencies before the final cutoff.
Hybrid Exchange Deployments After the EWS Shutdown
Microsoft clarified how hybrid deployments should prepare:
- On-premises mailboxes can continue using EWS
- Cloud mailboxes must move to Microsoft Graph
- Autodiscover will route apps to the correct mailbox location
- Only Exchange Server SE will support Graph calls to Exchange Online in hybrid setups
Organizations running hybrid environments should plan upgrades carefully to avoid compatibility issues during the transition.
FAQs
What is the Exchange Web Services shutdown?
The Exchange Web Services shutdown is Microsoft’s plan to permanently disable the EWS API in Exchange Online. Microsoft will begin blocking EWS by default in October 2026 and fully shut it down on April 1, 2027, requiring organizations to move to Microsoft Graph.
When will Exchange Web Services be shut down?
Microsoft will block Exchange Web Services by default starting October 1, 2026, and permanently shut it down in Exchange Online on April 1, 2027. After that date, EWS access will no longer be available or configurable.
Does the Exchange Web Services shutdown affect on-prem Exchange Server?
No. The Exchange Web Services shutdown applies only to Microsoft 365 and Exchange Online. On-premises Exchange Server deployments will continue to support EWS without changes.
Why is Microsoft shutting down Exchange Web Services?
Microsoft is shutting down Exchange Web Services because it no longer meets modern security, scalability, and reliability requirements. Microsoft Graph now provides near-complete feature parity and aligns better with current cloud security standards.
What should admins do before the Exchange Web Services shutdown?
Admins should review EWS usage, identify dependent applications, configure allow lists if needed, and begin migrating workloads to Microsoft Graph well before October 2026 to avoid service disruptions.
Can Exchange Web Services be temporarily re-enabled after blocking?
Yes. After October 2026, admins can temporarily re-enable Exchange Web Services using allow lists, but Microsoft warns this may cause service interruptions and is only a short-term option before the final shutdown.
What replaces Exchange Web Services after shutdown?
Microsoft Graph is the official replacement for Exchange Web Services. It supports email, calendar, contacts, and mailbox access for most scenarios previously handled by EWS.
How does the Exchange Web Services shutdown affect hybrid environments?
In hybrid setups, on-prem mailboxes can continue using EWS, but cloud mailboxes must move to Microsoft Graph. Autodiscover will route requests correctly, and Exchange Server SE is required for Graph calls to Exchange Online.
Will Microsoft extend the Exchange Web Services shutdown deadline?
No. Microsoft has confirmed there will be no extensions or exceptions beyond April 1, 2027. Organizations must complete migration before that date.
How can admins detect apps still using Exchange Web Services?
Admins can use EWS usage reports in the Microsoft 365 admin center and Microsoft’s diagnostic scripts to identify applications that still rely on Exchange Web Services.
