This feature enables Pulp users to track repository content sets as repository versions. A repository version represents an immutable set of content. A new repository version is created every time the set of content changes. New Users can create new repository versions are created by syncing content using an importer and by specifying which content to add or remove from the previous repository version. Any repository version can be deleted. Any repository version can be used to create a publication. Each publication can be distributed at a unique URL. As a result, content consumers can access multiple repository versions at the same time.