Fatal error: Uncaught Error: Class 'yii\base\Widget' not found in /var/www/up.arbitr-dolg.ru/vendor/yiisoft/yii2-bootstrap4/src/Widget.php:16 Stack trace: #0 {main} thrown in /var/www/up.arbitr-dolg.ru/vendor/yiisoft/yii2-bootstrap4/src/Widget.php on line 16