This policy setting controls whether Outlook can automatically upload calendar updates to Office.com.
If you enable this policy setting, Outlook enforces the "Single Upload: Updates will not be uploaded from the Published Calendar Settings dialog" option, and calendar updates are not uploaded. Users will not be able to change this setting.
If you disable this policy setting Outlook automatically publishes calendar updates to Office.com at regular intervals and users will not be able to change this.
If you do not configure this policy setting, when users publish their calendar to Office.com using the Microsoft Outlook Calendar Sharing Service, Outlook updates the calendars online at regular intervals unless they click "Advanced" and select "Single Upload: Updates will not be uploaded from the Published Calendar Settings dialog".