Omeka S is a new platform and not an upgrade to Omeka 2. Omeka 2 and Omeka S will continue to exist in parallel. Omeka S uses a multisite architecture that allows one installation to support multiple sites that share items, it has an API and is designed to connect with other systems like Fedora and DSpace. Omeka S models data as RDF triples and supports common vocabularies while not performing rule inference or enforcement.