How do I enable or disable Outlook shared calendar improvements?

What are shared calendar improvements?

Shared calendar improvements in Outlook allow faster and more reliable sync of shared calendars across web, mobile, and desktop. These enhancements improve update speed, permission handling, and consistency between devices.

How do I turn shared calendar improvements on or off in Outlook for Windows?

1. Open Outlook and go to File > Account Settings > Account Settings.
2. Select your Microsoft Exchange account and click Change....
3. Click More Settings, then go to the Advanced tab.
4. Check or uncheck Turn on shared calendar improvements.
5. Click OK, then restart Outlook.

This setting only affects shared calendars. Your personal calendars are unaffected, and you can toggle this feature at any time.

How do I know if a shared calendar is using the improved model?

Right-click the calendar and choose Properties. If it says Type: Folder containing Calendar items (REST), the calendar is using the improved model.

How do I upgrade a shared calendar to the new model?

1. Remove the shared calendar.
2. Re-add it using the latest version of Outlook. The calendar will auto-upgrade after syncing.