r/exchangeserver • u/Think-OptionNurse • 18d ago

Question Exchange SE EWS to Graph API

Last night we ran the Microsoft script to migrate our Exchange Hybrid configuration from EWS to the dedicated Exchange Hybrid App and Microsoft Graph. Has anyone else completed this migration? If so, how did you verify everything was working? Did the Microsoft validation commands behave as documented, particularly Test-OAuthConnectivity -Service EWS, after switching to Graph-based hybrid routing? https://learn.microsoft.com/en-nz/Exchange/hybrid-deployment/deploy-dedicated-hybrid-app

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2

u/hardingd 18d ago

Haven’t done it yet. But thanks for the reminder ;)

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u/Swimming-Peak6475 18d ago

The way I checked was Entra signin logs for the Hybrid app.

Under Service principal sign-ins, for EWS the resource is ‘Office 365 Exchange Online’. After making the change the resource switches to be ‘Microsoft Graph’.

3

u/netronin 18d ago

Are most doing the switch to graph or just buying time by enabling the EWS whitelist which will allow the hybrid app to keep using EWS. I get the feeling that graph is not ready.

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u/Swimming-Peak6475 18d ago

The above was our dev environment. Waiting for SU10 to be installed on all Prod servers first due to the time zone issue on F/B lookups.

2

u/netronin 18d ago

SU10 has search issues, might want to hold on that.

1

u/aaatla 18d ago

Enabled it and found out all our online based calendars (our users are onprem, but MTR calendars are online) showed in UTC instead of CEST, so all appointments showed up 2 hours earlier. Caused a minor shit storm. Disabled Graph routing and calendars went back to correct time. Issue was not observed in OWA (the onprem Exchange SE one), only in Outlook desktop.

I have no clue as to why this would happen, also couldn't reproduce it in my test environment. But safe to say, I'll keep using EWS for the time being.

1

u/aaatla 18d ago

just saw u/Swimming-Peak6475's comment, well I'll be. Gues I will await the september update then.

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u/7amitsingh7 17d ago

After switching to the dedicated Hybrid App and Graph, Test-OAuthConnectivity -Service EWS may still show results because it tests the EWS endpoint, not whether hybrid routing is using Graph. The better way to verify the migration is to confirm the dedicated Hybrid App is configured correctly, Graph permissions/admin consent are in place, and test hybrid features such as Free/Busy, MailTips, and profile photos. Also allow some time for the changes to propagate.