Microsoft has released Security Updates (SUs) for vulnerabilities found in:
Exchange Server Subscription Edition (SE)
Exchange Server 2019
Exchange Server 2016
SUs are available for the f...
Updated Sep 24, 2026
Version 4.0
Blog Post
We are experiencing a regression in our hybrid environment after installing Security Update 10 (SU10) and switching the Exchange Server Enterprise App mode to Graph Only.
Environment:
- Exchange Hybrid
- Scenario: An on-premises user checks the free/busy times of a cloud-hosted user in Outlook Classic running in Online Mode.
Behavior:
- The numerical free/busy availability data is present, but the detailed status text (e.g., Tentative, Busy, Out of Office) is missing or blank for cloud users.
Workaround:
- Rolling back the Enterprise App configuration from Graph Only back to EWS immediately restores the status text visibility in Outlook Classic.
Is this a known limitation of the Graph Only transition?
Bhalchandra_Atre-MSFTMicrosoft
I see the same F/B details, on EWS as well on Graph
Like this?
Then we have the same problem. On-premise user looking at an Exchange Online mailbox calendar.
Exchange SE SU10 in hybrid with Exchange Server Enterprise App mode to Graph Only.
yes, exactly
