Fatal error: Uncaught Error: Interface "Composer\Plugin\PluginInterface" not found in /usr/local/www/roundcube/vendor/roundcube/plugin-installer/src/RoundcubeInstaller.php:9 Stack trace: #0 {main} thrown in /usr/local/www/roundcube/vendor/roundcube/plugin-installer/src/RoundcubeInstaller.php on line 9