Abstract: A directory schema for directory applications or platforms that store common attributes in a distributed directory. According to the schema, a given attribute is stored in a directory together with a signature that identifies given information, e.g., the purpose and version of the attribute. Thus, when an attribute is migrated to a new value, e.g., upon the release of a new application version, the directory schema need not be extended. Rather, the attribute may be maintained in the schema is the same location as was used with an earlier application version.