4.2.4 - The repository shall have and use a convention that generates persistent, unique identifiers for all AIPs.
SP uses a systematic convention to generate unique and unambiguous identifiers for digital objects within the repository. This process creates a stable name and persistent reference for every object. Please the URI & File Naming Plan for details. An identifier may change if the Provider replaces an article with a new version of the same article. Please see 4.2.4. for more information.
Digital Preservation Policy Librarian