While Microsoft does not currently support any version of Exchange Server older than Exchange 2016 or 2019, we still allow customers with older versions of Exchange (Exchange 2013 or older) to bring their data / migrate to Exchange Online using Microsoft made migration tools.
We wanted to inform you of upcoming changes to the support for public folder migrations from older on premises Exchange servers to Exchange Online.
What’s changing
We are deprecating support for public folder migrations from Exchange Server 2010 and older versions to Exchange Online to reduce reliance on older systems and improve long-term service reliability. Public folder migrations from these on premises versions to Exchange Online (Public Folders and Microsoft 365 Groups) will be blocked starting October 1st, 2025. Public folder migration jobs will fail after this date. Organizations currently using Exchange Server 2010, or older versions who are planning to migrate public folders to Exchange Online (Public Folders and Microsoft 365 Groups) using Microsoft native migration tools will be impacted by this change.
What should impacted customers do
Customers migrating public folders from Exchange Server 2010 and older to Exchange Online can continue to use Microsoft migration tools until October 1st, 2025, but should complete their public folder migration by this date. After that date, all already started public folder migrations using Microsoft tools from Exchange 2010 or older will fail.
After that date, customers who want to migrate public folders from Exchange Server 2010 and older will need to migrate public folders to a newer Exchange Server version first and then proceed with the migration of public folders to Exchange Online.
Please note that we do not encourage customers to use those long unsupported versions of Exchange in any way. It is very important to keep your Exchange servers up to date. But we are aware of some such migrations still happening and wanted to let you know of this upcoming change.
Public Folder Team
