framework/db/mssql/PDO.php
public function getAttribute($attribute)
    {
        try {
            return parent::getAttribute($attribute);
        } catch (\PDOException $e) {
            switch ($attribute) {
                case self::ATTR_SERVER_VERSION:
                    return $this->query("SELECT CAST(SERVERPROPERTY('productversion') AS VARCHAR)")->fetchColumn();
                default:
                    throw $e;
            }
        }
    }
public function getAttribute($attribute)
    {
        try {
            return parent::getAttribute($attribute);
        } catch (\PDOException $e) {
            switch ($attribute) {
                case self::ATTR_SERVER_VERSION:
                    return $this->query("SELECT CAST(SERVERPROPERTY('productversion') AS VARCHAR)")->fetchColumn();
                default:
                    throw $e;
            }
        }
    }
Retrieve a database connection attribute.

It is necessary to override PDO's method as some MSSQL PDO driver (e.g. dblib) does not
support getting attributes.
@param int $attribute One of the PDO::ATTR_* constants.
@return mixed A successful call returns the value of the requested PDO attribute.
An unsuccessful call returns null.