Omeka is a tool for managing and publishing of digitized document and data collections for libraries, museums, museums, galleries, archives and universities. It makes it easy to create standardized records for documents without any special knowledge and to promote them in online exhibitions. It features a wide range of modules and themes to meet most needs, from students, for example to present their work with documents that can be easily consulted, to large inter-university libraries, to share their collections without any physical constraints and without giving the rights of its own heritage to Google via the Google Books digitization program.

The development of the first version of Omeka began in 2006, and version 1 was released on June 2, 2009 as a standalone content management system (CMS), in the style of websites of the time such as Wordpress. The version 2 was released on January 24, 2013. This was the first complete rewrite of the software (application), but based on the fairly popular Zend framework. The choice to use a platform meant that many components were available, and therefore the Omeka team could concentrate on developing features related to the tool itself. Finally, in view of new needs, particularly in terms of metadata standardization, multi-site and multilingual management, and the development of the semantic web, a rethink was quickly undertaken and a new rewrite began on August 12, 2013, with the new version released on November 20, 2017, still based on Zend, which later became Laminas, but with the powerful Doctrine ORM for database management.

Today, the use of Omeka 2, renamed Omeka Classic, for new collections is no longer justified. The technical underpinnings are obsolete, in particular version 2 of Zend has been abandoned, and the software no longer works with current environments, notably officially maintained versions of PHP. Similarly, the majority of plugins and themes are no longer maintained. All Omeka Classic features are now implemented in Omeka S and much more (IIIF integration, native RDF data with JSON-LD REST API, etc.). Numerous tools have been developed to facilitate migration, starting in 2017 with the Upgrade To Omeka S plugin and the Upgrade From Omeka Classic module, and next the Bulk Import module and the Omeka 2 Importer module from the Omeka team. In addition, in 2021 the Omeka team integrated a new interface for Omeka Classic, that is very close to the one of Omeka S (version 3 of Omeka 2), and migrated the main official themes.

This space contains all the information you need to map old themes and extensions with new ones, plus a tool to install Omeka S in one line or one file. It also includes all Omeka plugins, modules, classic themes and themes that users may not have requested to be added on the official site.