Microsoft EWS Retirement: what it means for Zoho Mail users

Microsoft EWS Retirement: what it means for Zoho Mail users

Microsoft has officially announced the retirement of Exchange Web Services (EWS) for Exchange Online.

If your organization is planning to migrate from Microsoft 365 to Zoho Mail, you may be wondering what this change means for you. The good news is that most Microsoft 365 migrations to Zoho Mail will continue to work as usual. However, there's one important exception that organizations should be aware of. 

What is Exchange Web Services (EWS)?

Exchange Web Services (EWS) is Microsoft's API that allows applications to access mailbox data stored in Exchange Online. For years, it has powered mailbox migrations, third-party integrations, archiving solutions, and email management tools.

Zoho Mail currently uses EWS to migrate data from Microsoft 365, including, primary mailboxes, contacts, calendars, shared mailboxes, and in-place archive mailboxes.

How does the EWS retirement affect Zoho Mail migrations?

The impact is limited to the migration of Microsoft 365 in-place archive mailboxes to Zoho Mail. 

Microsoft is replacing EWS with Microsoft Graph API for Exchange Online integrations. While Microsoft Graph supports most mailbox operations, it currently does not provide access to in-place archive mailboxes.

Because of this limitation, once Microsoft starts blocking EWS, Zoho Mail will no longer be able to migrate in-place archive mailboxes from Microsoft 365. The migration of primary mailboxes, contacts, calendars, and shared mailboxes from Microsoft 365 to Zoho Mail will continue to be fully supported without interruption.

What is the deadline?

  1. Microsoft will begin blocking Exchange Web Services (EWS) requests in Exchange Online on October 1, 2026.
  2. From this date onward, Zoho Mail will no longer be able to migrate Microsoft 365 in-place archive mailboxes. However, migrations of primary mailboxes, contacts, calendars, and shared mailboxes will continue to be fully supported.
  3. On April 1, 2027, EWS will be fully retired from Exchange Online, and any applications or services that still rely on EWS will stop functioning altogether.

What should you do?

If your organization needs to migrate in-place archive mailboxes, we strongly recommend completing the migration before October 1, 2026.  Here are a few steps to help you prepare:
  1. Identify users with in-place archive mailboxes in your Microsoft 365 Admin Center and estimate the amount of archive data to be migrated.
  2. Configure the migration in the Zoho Mail Admin Console by selecting In-Place Archive Mailbox as the mailbox type for the relevant users.
  3. Prioritize large or business-critical archive mailboxes so they are migrated first.
  4. Start your migration well ahead of the deadline to avoid any last-minute issues.
For detailed instructions, refer to the Migration from Microsoft 365 to Zoho Mail help documentation.

Plan ahead!

Organizations that do not migrate their in-place archive mailboxes before October 1, 2026 may permanently lose the ability to migrate archived mailbox data from Exchange Online to Zoho Mail, unless Microsoft introduces an alternative API in the future.

If you're planning a move from Microsoft 365 to Zoho Mail, now is a good time to review your migration strategy and ensure any archive mailbox migrations are completed before the deadline.

If you have any questions or need assistance planning your migration, feel free to reach out to our support team at support@zohomail.com. We'll be happy to help.