Microsoft Exchange Online Public Folders: Why Migration Can't Wait

If your organization still relies on Microsoft Exchange Online Public Folders, now is the time to modernize that data before critical migration pathways are restricted.  

This guide explains what’s changing, what it means for your environment, and how to plan a transition to a modern solution using AvePoint Fly — while those pathways are still available.

These changes directly affect how organizations back up, migrate, and maintain Public Folder data, particularly in environments that rely on automation or third-party integrations. 

What's Changing with Microsoft Exchange Online and EWS Access?

Beginning October 1, 2026, Microsoft will restrict programmatic access to Exchange Online Public Folders — limiting it to supported Outlook clients and bulk import/export scenarios. Microsoft has stated that it will no longer support APIs for “creating, reading, updating, or deleting Public Folder data after October 2026.”

This change is closely tied to Microsoft’s broader retirement of Exchange Web Services (EWS) in Exchange Online: a foundational API that many tools rely on for accessing Public Folder data. This shift also follows increased scrutiny of legacy protocols, including after the Midnight Blizzard incident in January 2024, reinforcing Microsoft’s move toward more secure, modern alternatives.

In practical terms, this means organizations will soon lose the ability to rely on automated tools and integrations to manage Public Folder data, thus making proactive migration planning essential.

What the Restriction Means for Your Organization  

If your organization still actively uses Exchange Online Public Folders – or stores legacy data within them – this change introduces several operational limitation:

1. Loss of Programmatic Access

Third-party tools and custom integrations that rely on Exchange Web Services will no longer be able to access Public Folder data programmatically once restrictions take effect.

2. Backup and Recovery Limitations

Without programmatic access, Public Folder data can no longer be actively backed up or restored. This limitation affects all backup solutions, including AvePoint Cloud Backup for Microsoft 365, where existing data may be retained, but only export capabilities will remain available.

3. No API Replacement in Microsoft Graph

Microsoft has confirmed there is no equivalent support for Public Folders in Microsoft Graph, with no APIs available for creating, reading, updating, or deleting Public Folder data.

4. Reduced Automation and Migration Flexibility

Workflows that depend on automation – including migration, synchronization, and reporting – will be significantly limited as access to Public Folder data becomes restricted.

Taken together, these limitations significantly reduce the ability to manage and migrate Public Folder data at scale using automated approaches. As a result, the need to transition to modern, supported alternatives becomes increasingly clear.

Why Shared Mailboxes Are a Practical Replacement for Public Folders  

For many Public Folder use cases, Exchange Online Shared Mailboxes provide a familiar and supported alternative by:

• Enabling shared access to a central mailbox so multiple users can read, manage, and respond to messages from a single address.
• Supporting team-based communication identity, allowing users to send messages using “Send As” or “Send on Behalf Of” permissions.
• Providing shared calendar functionality so teams can coordinate schedules and manage events in one place.
• Maintaining a familiar Exchange Online experience through full integration with Outlook and existing workflows.

Shared mailboxes are fully supported by Microsoft Graph and do not require a separate license for standard usage (up to 50 GB), making them a cost-efficient option for many scenarios. For organizations that have used Public Folders to manage shared email, calendars, contacts, or tasks, they offer a direct and supported path forward without relying on legacy APIs.  

As programmatic access to Public Folders becomes restricted, shared mailboxes provide a supported and scalable destination for preserving access to shared content.

Migrate Public Folders to Shared Mailboxes with AvePoint Fly

Migrating Public Folder data to Shared Mailboxes requires a solution that preserves structure, maintains accessibility, and scales across environments. AvePoint Fly provides a supported path to complete that transition.

What Fly Can Migrate

Supported content types include:

• Mail and post items, including messages and threads.
• Calendar items, including meetings and recurring events.
• Contacts, tasks, notes, and journal entries.

Key item properties are preserved, including:

• Attachments and embedded content.
• Categories and flags.
• Sensitivity labels applied to supported items.

These capabilities ensure that core business content stored in Public Folders can be migrated to Shared Mailboxes with structure and key metadata preserved.

How Migration Works with AvePoint Fly

AvePoint Fly follows a structured migration process consisting of two main phases:

Phase 1: Prepare

1. Assess Public Folder usage, including content, structure, and size to determine what should be migrated and where — whether content should be moved to shared mailboxes or if large folders should be split across multiple destination boxes.
2. Establish secure connections between source Public Folders and the target Exchange Online environment through AvePoint Online Services.
3. Configure destination Shared Mailboxes and define access models for post-migration use.
4. Define migration scope, policies, and user mappings, and validate the approach through a pilot migration.  

Phase 2: Execute

1. Run full migrations based on your defined configuration policy.
2. Perform incremental migrations to capture new or updated content.
3. Validate results to capture new or updated content.
4. Complete final migration steps, export reports, and perform cleanup.

For larger environments, migrations can be executed in stages, with reporting available throughout each phase.

Support Your Migration with Confidence

Many organizations manage migrations independently using AvePoint Fly, with its built-in capabilities to plan, execute, and validate each stage of the process. AvePoint Fly is designed to help IT teams of all sizes plan, execute, and validate a Public Folder migration with confidence.

For more complex environments, additional support is available through AvePoint’s extensive partner network to assist with planning, execution, and large-scale migration management.  

Get Ahead of the EWS Retirement  

The current timeline provides a limited opportunity to complete migrations while programmatic access is still available.

Once programmatic access is restricted in October 2026 and EWS is fully retired in April 2027, migration options will become significantly more limited. Planning and executing migrations ahead of these changes allows organizations to complete transitions while tooling and APIs remain available. 

Ready to evaluate your Exchange Online Public Folder environment? Get started with AvePoint Fly.