Is Multi Tenant Organization Impacted by EWS deprecation

Question

Is Multi Tenant Organization Impacted by EWS deprecation

Jānis Semjonovs 50

Hello!
Have question about EWS decommission and MTO. As I understand from this change MC1446796 - Migrate Free/Busy, MailTips, and Calendar Sharing before EWS deprecation, need to migrate cross-tenant policies. Did not find specifically stated that this is also needed to be done on Multi tenant organization set up. From Provided powershell commands see that there is MTO using Free/Busy. Did not find anywere clearly stated that MTO is impacted.

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Answer 1

Vasil Michev 128.3K MVP Volunteer Moderator

No. This only affects Exchange organizational relationships, MTO does not involve such. The replacement is based on cross-tenant access policies, which is the same configuration as used by MTO. In effect, you can think of this as enhancing support for cross-tenant access policies/MTO to also cover Exchange org relationships.

Jānis Semjonovs 50 Reputation points

2026-09-08T13:01:34.7633333+00:00

Hi
Thank You for response. Are You sure about this as in Microsoft documentation it states :

The calendar sharing feature for MTO utilizes Organization relationships in Exchange Online. The organization relationship will share all users calendar availability and must also be set up by the other tenants in your MTO for free/busy information to be shared.
Vasil Michev 128.3K Reputation points MVP Volunteer Moderator

2026-09-08T13:49:32.65+00:00

Hm, guess I missed the memo on that one. I don't recall free/busy sharing being part of MTO when it initially released, I seem to have overlooked the updates... In any case, apologies for misleading you above.

I guess we will have to manually update the existing cross-tenant access policies in such scenarios, as Microsoft has not mentioned that they will automatically be updated. But let me ping few folks for more up-to-date info, so I don't mislead you again.

P.S. If you have an existing MTO configuration with free/busy sharing enabled, can you check the current state of the cross-tenant access policies and verify whether the corresponding "capabilities" are present?
Jānis Semjonovs 50 Reputation points

2026-09-09T05:25:18.2966667+00:00

Hi
So running in change provided powershell comman-
Get-OrganizationRelationship | Format-List Name, DomainNames, Enabled, FreeBusyAccessEnabled, FreeBusyAccessLevel, FreeBusyAccessScope, MailTipsAccessEnabled, MailTipsAccessLevel, MailTipsAccessScope

In return we get MTO - with tenant ID
FreeBusyAccessEnabled : True