One question MC1446796 - Migrate Free/Busy, MailTips, and Calendar Sharing before EWS deprecation
Yesterday we got the information in MC that FreeBusy via OrgRelationships is also affected by the EWS deprecation staring with 1st october.
Because orgrelationships, sharingpolicies and availabilityaddressspaces in EXO are also EWS-based.
If we need more time to migrate from OrgRelationships to CrossTenantAccessPolicies, we should follow the guidance of the latest blog we published: https://techcommunity.microsoft.com/blog/exchange/exchange-online-ews-your-time-is-almost-up/4492361
We only have this single UseCase (OrgRelationships / FreeBusy) to extend EWS Usage.
Which ApplicationID do I have to put on the EwsAllowList?
Published Aug 04, 2026
Version 1.0
