The shutdown of Exchange Web Services (EWS) in Exchange Online (Microsoft 365), planned for October 1, 2026 (initial blocking) and April 1, 2027 (full shutdown), will affect any third-party tool that relies on this legacy protocol to access mailbox data.
While many vendors are currently migrating to the Microsoft Graph API, those that have not updated their integrations will stop functioning. The categories of tools most affected include backup/archiving solutions, CRM integrations, and workspace management tools.
Confirmed Third-Party Tools & Vendors Affected
The following tools have either issued official guidance regarding the EWS retirement or have been identified by Microsoft as significant users of the protocol:
- Backup & Archiving Solutions:
- Veeam: Specifically Veeam Backup for Microsoft 365. Veeam has confirmed that while they use Graph for many tasks, EWS is still used for certain Exchange backup operations and must be fully transitioned.
- Barracuda Message Archiver (BMA): Confirmed use of EWS; Barracuda is currently aligning with Microsoft’s timeline to migrate to Graph.
- MailStore (Server & SPE): Affects mailbox importing, archiving, and public folder access. MailStore has warned that EWS-based archiving profiles will fail after the shutdown.
- Veritas (Arctera Insight Platform): Currently assessing EWS dependencies to ensure continued functionality.
- CRM & Sales Productivity:
- Salesforce: Affects Lightning Sync for Microsoft Exchange. Salesforce is advising users to migrate to Einstein Activity Capture or update components to avoid sync failures.
- HubSpot: Many older Exchange integrations for calendar and email logging use EWS.
- Video Conferencing & Room Management:
- Zoom: Specifically Zoom Rooms and Zoom Workspace Reservation. Older configurations using EWS + Application Impersonation will stop working (some as early as 2025 due to intermediate RBAC retirements).
- Cisco/Polycom: Room systems managed by connectors that sync with Exchange calendars via EWS.
- Robin / Flexopus / yoffix: Desk booking and conference room scheduling tools that rely on EWS for real-time calendar availability.
- Security & Automation (iPaaS):
- Palo Alto Networks (Cortex XSOAR): Their EWS v2 integration and playbooks for email processing/incident response will be impacted.
- Zapier / Workato: Older Microsoft Exchange (Legacy) triggers and actions often utilize EWS rather than the modern Office 365 Outlook (Graph) connector.
- Codeless Platforms (BPA Platform): Widely used for integrating EWS with ERP systems like SAP Business One, Sage, and NetSuite.
Common Use Cases at Risk
If your organization uses a tool (even a custom-built one) for the following, it is likely affected:
- Public Folder Access: Microsoft has stated that programmatic access to Public Folders will be severely restricted after October 2026, as Graph does not have full parity for this.
- Mailbox Migrations: Tools used to move data between tenants that haven’t moved to Graph-based bulk import/export.
- Service Accounts / Impersonation: Tools that use a single super-user service account to read many mailboxes (Application Impersonation) are the primary target of this shutdown for security reasons.
How to check your own environment
Microsoft has provided tools for admins to see exactly which third-party apps are still making EWS calls in their tenant:
- EWS Usage Reports: Available in the Microsoft 365 Admin Center.
- EWS Analyzer: A script/tool provided by Microsoft to identify specific AppIDs still using the legacy protocol.
- AppID Allow List: Starting in early 2026, admins will be able to Allow List specific apps to keep EWS working until the final April 2027 deadline.