Deactivation of Exchange Web Services

Exchange Web Services is being phased out: What organisations need to know now

Microsoft is discontinuing Exchange Web Services (EWS) in Exchange Online. Organisations running applications, integrations or automations based on EWS should review their dependencies in good time and plan any necessary adjustments.

For many years, EWS has been a key interface for accessing Exchange Online content. Many third-party products, migration tools, archiving and backup solutions, CRM or ERP integrations, as well as custom scripts, may use EWS. In future, modern interfaces such as the Microsoft Graph API and, for certain administrative scenarios, the Exchange Online Admin API should be used.

EWS dependencies should be identified, assessed and gradually reduced before October 2026 to ensure that no unexpected service disruptions occur when EWS is deactivated.

Why is EWS being phased out?

EWS was originally developed for older Exchange integration scenarios. By phasing it out, Microsoft aims to reduce the use of legacy interfaces and migrate applications to more modern, secure and cloud-ready APIs.

The strategic target architecture for many application scenarios is Microsoft Graph. This provides access to Microsoft 365 data and functions via modern REST-based interfaces, OAuth-based authentication and more granular authorisation models.

Applications and technical integrations with EWS dependencies

This primarily affects applications and technical integrations that still use EWS. Typical examples include:

• Backup and archiving solutions
• Migration tools
• CRM and ERP integrations
• Signature and workflow solutions
• Mobile or industry-specific applications
• Custom scripts, automations and legacy applications
• Hybrid or near-coexistence scenarios, provided these still contain EWS dependencies

How can you tell if EWS is being used?

The central starting point is the Exchange Web Services Usage Report in the Microsoft 365 Admin Centre. The report shows which applications use EWS SOAP Actions and the volume of calls made to them.

Navigation in the Microsoft 365 Admin Centre: Reports → Usage → Exchange → EWS Usage

Recommended steps for customers

1. Review the EWS Usage Report in the Microsoft 365 Admin Centre.
2. Check application IDs and identify whether they are Microsoft, third-party or in-house developments.
3. Check with vendors to see if a version without EWS dependency is available.
4. Check your own applications for EWS Managed API, ExchangeService, SOAP calls, Autodiscover and application impersonation.
5. Plan a migration path – typically to Microsoft Graph; for certain administrative scenarios, to the Exchange Online Admin API where necessary.
6. Test changes in a controlled manner before blocking production dependencies.

Identify relevant Microsoft 365 changes at an early stage with CANCOM

Microsoft 365 is constantly evolving. New features, technical changes, potential risks and end-of-life announcements are an integral part of modern cloud environments. CANCOM’s M365 Pro-Active Services help Microsoft 365 administrators identify relevant developments at an early stage, assess their impact and optimally prepare their own environment for them.

In the context of the EWS decommissioning, this means that CANCOM assists customers not merely with an isolated readiness assessment, but as part of its general Microsoft 365 operational and configuration support.

The aim is to highlight relevant changes at an early stage, jointly assess configurations and provide expert guidance on any necessary adjustments.

Stay one step ahead of changes to Microsoft 365. With CANCOM M365 Pro-Active Services, you receive regular updates, structured reports and practical recommendations for action regarding relevant changes in your Microsoft 365 environment – from release changes and security insights to tenant configuration.

Service modules under CANCOM M365 Pro-Active Services