October 1, 2026
A new Graph API mailbox migration project gives MigrationWiz customers a modern path forward while EWS remains available for workloads not yet supported by Microsoft Graph.
As many MigrationWiz customers are aware, Microsoft is retiring Exchange Web Services (EWS) in Exchange Online. Microsoft announced that EWS will begin being disabled globally in October 2026, with full disablement scheduled for April 2027. Microsoft is encouraging organizations and application providers to move Exchange Online workloads to Microsoft Graph.
For MigrationWiz customers, that transition is already underway.
MigrationWiz’s new Graph API-based Mailbox project is now generally available, giving customers a new way to migrate Exchange Online mailboxes using Microsoft Graph instead of EWS.
At the same time, MigrationWiz will support both Graph API and EWS mailbox migration options during the transition. This gives customers flexibility to choose the approach that fits their project and the workloads they need to migrate.
A New Path for Mailbox Migrations
The retirement of EWS represents a significant change for organizations and migration providers that have relied on the technology for years.
Microsoft Graph is Microsoft’s strategic API platform for accessing Microsoft 365 services. Microsoft describes Graph as providing improvements in security, simplicity, and efficiency compared with EWS, including modern OAuth-based authentication and REST-based APIs.
MigrationWiz is embracing that transition.
With the new Graph API Mailbox project, customers have a modern migration path for Exchange Online mailbox migrations as Microsoft moves the platform away from EWS.
But the transition isn’t one-size-fits-all.
Microsoft has not yet delivered Graph API support for every mailbox migration scenario. In particular, customers migrating Archive Mailboxes, Public Folders, or Microsoft 365 Group mailboxes may still require capabilities that are not currently available through the Graph-based MigrationWiz project.
For those scenarios, MigrationWiz customers can continue using the EWS Mailbox project to migrate supported items and workloads.
That means customers don’t have to choose between preparing for the future and completing migrations that have requirements Graph doesn’t yet support.
Two Mailbox Migration Paths
MigrationWiz customers now have two mailbox migration approaches:
Graph API Mailbox Project
Use the new Graph-based project for supported Exchange Online mailbox migration scenarios and begin building your migration processes around Microsoft’s modern API platform.
EWS Mailbox Project
Continue using the EWS-based project when your migration requires functionality that isn’t currently supported through Graph, including applicable Archive Mailbox, Public Folder, and Microsoft 365 Group mailbox scenarios.
This approach gives migration teams a practical path through the EWS transition.
As Microsoft continues closing some remaining API gaps, customers can adopt Graph where it makes sense while continuing to use EWS for workloads that still depend on EWS capabilities.
What Happens to EWS Between Now and April 2027?
The EWS transition is happening in phases.
Starting in October 2026, Microsoft will begin globally disabling EWS for Exchange Online organizations. Tenant administrators can manage EWS access during the transition and, where permitted by Microsoft’s controls, continue using EWS while they complete migration plans.
That provides organizations with additional time to transition applications and complete projects that still depend on EWS.
But that window is temporary.
In April 2027, Microsoft will fully disable EWS in Exchange Online. After that point, EWS requests to Exchange Online will be permanently blocked.
For MigrationWiz customers, that means planning should begin now.
What About Archive Mailboxes, Public Folders, and Group Mailboxes?
This is an important consideration for customers planning migrations during the EWS transition.
Microsoft has identified several remaining parity gaps between EWS and Microsoft Graph. Its current roadmap includes targeted Q4 2026 availability for full-fidelity import and export of Archive Mailboxes, Public Folders, and Microsoft 365 Group mailboxes. However, Microsoft also states that Generic Public Folder CRUD and Generic Microsoft 365 Group mailbox CRUD will not be added to Microsoft Graph.
Because these capabilities are still evolving, customers with these workloads should evaluate their migration requirements carefully.
If your project requires Archive Mailbox, Public Folder, or Microsoft 365 Group mailbox migration capabilities that are not supported by the Graph API Mailbox project, you can continue to use the EWS Mailbox project while EWS remains available and permitted for your tenant.
This is especially important for organizations with complex or legacy Exchange environments. Don’t assume that every mailbox-related workload can be handled through the new Graph project simply because the primary mailbox can.
Using the New Graph API Mailbox Project
The new project type gives MigrationWiz customers an opportunity to start preparing for the post-EWS environment today.
For new projects, evaluate which workloads you need to migrate and determine whether the Graph API Mailbox project supports those requirements. If it does, you can begin using the new project and familiarize your team with the new migration workflow.
If your project includes workloads that still require EWS capabilities, plan accordingly and use the EWS Mailbox project where appropriate.
For MSPs managing multiple customers, this distinction is particularly important. Migration projects don’t all have the same requirements, and the transition to Graph may happen at different speeds depending on the workloads involved.
What About Existing EWS Migrations?
Organizations that already have mailbox migrations planned or underway should evaluate each project individually.
If an existing project relies on EWS, the October 2026 transition does not necessarily mean the project must stop immediately. Microsoft is providing a transition period during which tenant administrators can manage EWS access, subject to Microsoft’s controls.
However, organizations should not treat that transition period as a reason to postpone planning.
April 2027 is the final deadline for EWS in Exchange Online.
Migration projects can involve significant planning, testing, scheduling, user communications, and validation. Moving supported projects to the Graph API-based MigrationWiz project sooner gives teams more time to incorporate the new approach into their migration operations.
At the same time, customers with workloads that still require EWS capabilities should identify those requirements now and plan their migration windows accordingly.
A Modern Foundation for What’s Next
The move from EWS to Microsoft Graph is more than an API change. It represents Microsoft’s broader shift toward modern, REST-based interfaces and more granular security and governance for Microsoft 365 applications.
The Graph API Mailbox project is now generally available, giving customers a modern path for supported Exchange Online mailbox migrations.
And because MigrationWiz will continue to provide an EWS Mailbox project during the transition, customers can choose the appropriate migration path based on the workloads in their project.
For MSPs, that means you can begin incorporating the Graph API project into your standard migration methodology while maintaining a path for customers with workloads that still require EWS.
For IT teams, it means you can start planning future mailbox migrations around the technology Microsoft is moving toward without losing access to EWS-based capabilities you still need today.
Don’t Wait Until 2027
EWS may still be available during the transition, but its end is no longer uncertain.
October 2026: Microsoft begins globally disabling EWS in Exchange Online.
April 2027: EWS is fully disabled.
Today: MigrationWiz’s new Graph API-based Mailbox project is Generally Available.
The right migration approach depends on what you’re moving.
If you’re migrating supported Exchange Online mailbox content, start evaluating the new Graph API Mailbox project now. If your project includes Archive Mailboxes, Public Folders, Microsoft 365 Group mailboxes, or other functionality that still requires EWS capabilities, factor that into your migration timeline and continue using the EWS Mailbox project where appropriate.
MigrationWiz is ready for the next generation of mailbox migrations with both Graph API and EWS options to help you navigate the transition.