Microsoft Confirms Exchange Web Services Shutdown for Exchange Online in 2027

Microsoft has already warned customers about risky local Exchange Online mailbox moves, and now the company has delivered another major Exchange-related announcement. This time, the focus is on the long-term future of Exchange Web Services.

Microsoft confirms Exchange Web Services shutdown timeline

Microsoft has confirmed that the Exchange Web Services (EWS) API for Exchange Online will shut down completely on April 1, 2027, ending almost two decades of service.

EWS has served as a cross-platform API for accessing Exchange mailbox data, including email messages, calendar meetings, and contacts. It supports both Exchange Online and on-premises Exchange versions going back to Exchange Server 2007.

Key dates administrators need to know

Microsoft outlined a phased retirement plan that stretches across 2026 and early 2027.

• By the end of August 2026, admins who configure application allowlists can avoid automatic blocking.
• In September 2026, Microsoft will auto-populate allowlists for tenants that did not create their own, based on observed usage.
• Starting October 1, 2026, EWS will be blocked by default in Exchange Online.
• On April 1, 2027, Microsoft will shut down EWS completely, with no exceptions.

Admins can keep EWS running temporarily after October 2026 by relying on application allowlists. Microsoft also plans to run temporary “scream tests” that disable EWS to expose hidden dependencies before the final cutoff. IT administrators will receive monthly Message Center notifications with tenant-specific usage reports and reminders.

The retirement applies only to Microsoft 365 and Exchange Online. On-premises Exchange Server deployments will continue to support EWS.

For developers, Microsoft recommends migrating to the Microsoft Graph, which now offers near-complete feature parity with EWS for most scenarios.

Hybrid Exchange environments explained

Microsoft also clarified how hybrid environments should prepare for the transition.

• On-premises mailboxes can continue using EWS.
• Cloud mailboxes must move to Microsoft Graph.
• Autodiscover will guide applications to the correct mailbox location.
• Only Exchange Server SE will support Graph calls to Exchange Online in hybrid setups.

According to Microsoft, EWS no longer meets modern requirements for security, scale, and reliability.

This shutdown does not come as a surprise. Microsoft first warned in 2018 that EWS would stop receiving new features. A follow-up notice in September 2023 confirmed that retirement would begin in October 2026, giving organizations several years to plan migrations.

In other Exchange and Azure news, Microsoft has started enforcing TLS 1.2 for Azure Blob Storage and has pushed the Sentinel migration deadline to 2027, signaling a broader push toward modern security standards across its cloud services.

Via BleepingComputer