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Any setting other than None will trigger authentication if the user is not already authenticated. 
If you are collecting Web Server Environment Variables, you will need to select an authorization level other than None.
Enrollment Flow Visibility
Prior to Registry v3.2.0, all logged in users can obtain a list of available Enrollment Flows via People >> Enroll.
As of Registry v3.2.0, this menu is no longer available to non-Administrative users. Links to specific Enrollment Flows can be made available in the My Identity menu by ticking the Enable My Identity Shortcut setting.
Identity Matching
COmanage Registry can perform identity matching when enrollment is performed. This is the process of checking for existing CO People that might match the person being enrolled. Note that matching only happens during the execution of an enrollment flow, now when manually adding a new CO Person. The following matching policies are available:
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