code: public static function getDbVersion()
  		{
  			try {
  				// Open Connection if closed
  				Yii::$app->db->open();
  			} catch (Exception $e) {
  				//ignore
  			}
  
  			return Yii::$app->db->pdo->getAttribute(PDO::ATTR_SERVER_VERSION);
  		}
docs: * Gets the current DB Version of Yii2
  
  @return mixed