Microsoft 365: Temporarily Re-enabling EWS During Migration

Microsoft is retiring EWS in Exchange Online / Microsoft 365. This change does not apply to Exchange Server installed on the customer infrastructure.
For this reason, when migrating from 20.04.xx to the new connector generation (24.08 or 26.04), Microsoft 365 must move to Microsoft Graph.
Key datesFrom October 1, 2026
Microsoft begins progressively blocking EWS in Exchange Online tenants that have not explicitly configured the available exception.From April 1, 2027: final shutdown
EWS will be permanently disabled in Exchange Online and can no longer be re-enabled through the temporary administrative setting.
If an EWS integration stops working during migration
During the transition period, Microsoft still allows administrators to temporarily re-enable EWS.
The Microsoft 365 administrator can manage the 
EWSEnabled setting and, where required, the list of authorized EWS applications.Temporary workaround
Re-enabling EWS should only be used to keep the service operational while completing the migration to Microsoft Graph. It is not a permanent solution.
Recommended approach for vtenext
If the legacy 20.04.xx connector stops communicating with Exchange Online after Microsoft blocks EWS:
evaluate whether EWS should be temporarily re-enabled to avoid an immediate service interruption;
migrate Exchange Connector from 20.04.xx to 24.08 or 26.04 using the module registration procedure;
configure Office365 with Microsoft Graph;
reconnect users if required;
verify synchronization;
remove the dependency on EWS once migration is complete.
If Exchange Connector is already on version 24.08, moving to 26.04 is a standard ZIP module upgrade and does not require the structural migration again.
Microsoft reference
Exchange Online EWS: Your Time Is Almost Up