What's changing, what you need to do, and what to expect

Overview

In October 2026, Microsoft is retiring the EWS API that Keepit uses to back up Exchange data. Two things change:

• Exchange connectors created before Keepit release 10.19 must be reauthenticated to grant new permissions.
• Public Folders will no longer be supported — backup and restore stop in October 2026.

More details here.

⚠️ Action required

Reauthenticate your Microsoft 365 connectors with Exchange data before October 2026 to avoid backup gaps. 

Reauthentication is done from the Connectors page. After reauthenticating, your connector enters a migration queue: existing backups continue while the migration completes. 

Connectors created after release 10.19 are already ready and require no action. 

Public Folders: End of support

Microsoft's Graph API does not support Public Folders. From October 2026:

• Backup and restore stop. 
• Previously backed-up data remains available for browsing and downloading in the Deleted Items view.

If Public Folders is your only configured data type, your connector will show a critical health status.

Exchange: Reauthentication required

Reauthentication grants Keepit the new permissions required by Microsoft's Graph API. Which connectors need it:

If you don't reauthenticate before October 2026

You can still reauthenticate after October. Backups will resume, but Exchange data won't be backed up during the gap.

Backup size & continuity

After migration, your Exchange backup size may increase. This is expected: the Graph API stores emails in FTS format, which is larger than the MIME format used by EWS. 

Keepit will not re-back up existing data from scratch — only new changes are captured after migration. All previously backed-up data remains available for browsing, downloading, and restoring.

Restore after migration

Because EWS (MIME format) and Graph API (FTS format) are different, Keepit includes a built-in converter, which will automatically convert MIME-format data when you initiate a restore. This means that data backed up before and after the migration can both be fully restored.