The system-assigned identifier is a version number that CentraSite maintains for its own internal use. CentraSite automatically assigns this identifier to an object when a version of the object is created. The system-assigned identifier is numeric and always has the format MajorVersion.Revision. The MajorVersion number is incremented by one each time you create a new version of the object (for example, 1.0, 2.0, 3.0). If the revisioning feature is enabled for your registry, the Revision number is incremented when updates are made to the object (for example, 1.0, 1.1, 1.2). You cannot delete or modify an object's system-assigned identifier.

The user-assigned identifier is an optional identifier that you can assign to a specific version of an object. This identifier does not need to be numeric. For example, you might use values such as “V2 Alpha” or “V2.1 Build 0921” to identify a particular version of an object.