MicrosoftIn preparation for this we changed our CAS Mailbox Plans to "EWSEnabled" False, and then set everyone's CAS Mailbox setting "EWSEnabled" to False as well except for a few service account mailboxes that use EWS with OAuth 2, but this broke Outlook Classic free/busy lookups, so EWS is still used by Outlook.
Nino_Bilic How will this be handled by Microsoft once EWS calls to Exchange Online are disabled on Oct 2026? Outlook Classic is supported till 2029.
MicrosoftThe bottom line is - all Microsoft apps (just like 3rd party apps) have to solve their reliance on EWS by then.
