Fatal error: Uncaught Error: Class "Roundcube\Composer\ExtensionInstaller" not found in /usr/local/www/roundcube/vendor/roundcube/plugin-installer/src/PluginInstaller.php:5 Stack trace: #0 {main} thrown in /usr/local/www/roundcube/vendor/roundcube/plugin-installer/src/PluginInstaller.php on line 5