Overview
After years of warnings, Microsoft announced the final retirement of Exchange Web Services (EWS) for Exchange Online. The legacy API will be fully disabled in October 2026, and all customers must transition to Microsoft Graph to maintain email, calendar, and contact integrations.
Key Timeline
- 2023 – Microsoft publicly announces EWS retirement.
- 2025 – Confirmation that Microsoft 365 and Office 365 F1/F2 licenses lose EWS access on March 1 2026.
- October 2026 – EWS is disabled for all Exchange Online tenants.
- 2027 – Any remaining “EWSEnabled” toggles are ignored; EWS ceases to function.
Why Microsoft Graph?
Microsoft Graph is the unified API platform introduced in 2015. It provides modern, secure, and extensible access to Microsoft 365 services, Windows, Azure, and cross‑platform endpoints (iOS, Android). Graph supports richer data models, better performance, and ongoing feature updates.
Migration Path
- Assess existing integrations: Identify all applications, third‑party tools, and in‑house scripts that rely on EWS.
- Map EWS calls to Graph endpoints: Use Microsoft’s migration guide to replace EWS operations (e.g., GetItem, FindItem) with Graph equivalents (e.g., /messages, /events).
- Update authentication: Switch from basic/NTLM to Azure AD OAuth 2.0 tokens.
- Test in a sandbox: Validate functionality, performance, and permission scopes before production rollout.
- Deploy and monitor: Roll out changes gradually, monitor logs for errors, and adjust permission scopes as needed.
Temporary Work‑around
Administrators can set the EWSEnabled property to null via Exchange Online PowerShell. This disables the built‑in restriction, allowing EWS calls to continue until the final 2027 cut‑off. However, this is a short‑term fix and does not guarantee future functionality.
Impact on Users
Without migration, email‑based workflows—such as automated ticketing, CRM sync, and custom reporting—will stop working once EWS is disabled. Organizations using F1/F2 licenses will lose EWS access as early as March 2026.
Preparing Your Organization
- Conduct an inventory of all EWS‑dependent solutions.
- Allocate development resources to rewrite integrations using Graph.
- Leverage Microsoft’s Graph SDKs for .NET, Java, JavaScript, and Python.
- Update security policies to reflect OAuth token usage.
- Communicate timelines to business units and set realistic rollout milestones.