Fork CMS 3.5 is an update to the user-friendly content management system Fork CMS. It has been upgraded to run on the Symfony framework, utilizing many of Symfony's components like the HTTP kernel and dependency injection container. This provides a more standardized foundation and allows the developers to contribute to open source by building on existing Symfony components rather than recreating features. Future updates will continue integrating additional Symfony components such as Twig templating and the SwiftMailer library.