Joomla 4 is a huge generation of Joomla CMS. Joomla 4 presents many new great features, raise the minimum supported PHP version to PHP 7 as well as remove previously deprecated functionality. Joomla 4.0 is based on Joomla! Framework 2.0 and new core User Interface that is worth looking forward to. Joomla 4 is intended to give Joomla users large functionality improvements with limited backward compatibility breaks. Going from 3.9 to 4.0 is a migration. You would need to upgrade your J3.9 to J3.10, which will be available the day J4.0 is stable. JOOMLA RELEASE ROAD MAP Joomla 4.0 and...