MC1227454: Exchange Web Services (EWS) retirement update

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Major Update: This post contains a significant change that may impact your organisation.

[Introduction]

We're updating the timeline and process for the retirement of Exchange Web Services (EWS) in Exchange Online. As previously announced, EWS will be retired in favor of Microsoft Graph , which offers improved security, modern authentication, and broader capability support. A phased disablement begins October 1, 2026 , with permanent shutdown starting April 1, 2027.

[When this will happen:]

• Phased EWS disablement begins: October 1, 2026
• Full and permanent EWS retirement: April 1, 2027
• EWS App AllowList feature availability: Coming soon (before retirement milestones)

[How this affects your organization:]

Who is affected:

• Organizations using custom or vendor applications that rely on EWS
• Workflows involving mail, calendar, or integrations that use EWS
• This change only impacts Exchange Online; Exchange Server (on-premises) is not affected

What will happen:

• Beginning October 1, 2026 , EWS will be blocked unless the tenant configures an AppID AllowList and sets EWSEnabled=True.
• Without admin action, Microsoft will set EWSEnabled=False and EWS apps will stop working. Tenant admins will be able to re-enable EWS if necessary.
• Temporary “scream tests” may occur before October 2026 to help identify dependencies.
• After April 1, 2027 , EWS access will be permanently removed with no re-enablement.
• No changes are being made to EWS in Exchange Server (on-premises).

[What you can do to prepare:]

• Review EWS usage in the Microsoft 365 admin center or using published scripts to identify dependent applications.
• Begin migrating any remaining EWS-based workflows to Microsoft Graph , which provides near-complete API parity.
• If EWS is required after October 2026 , configure an AppID AllowList and set EWSEnabled=True before end of August 2026.
• Communicate these changes internally and update documentation.

Learn more:

• Deprecation of Exchange Web Services in Exchange Online
• EWS Retirement Process overview

[Compliance considerations:]

No compliance considerations identified, review as appropriate for your organization.