public function getHistory()
    {
        $history = array(
            1 => new MaintenanceState(json_decode($this->getDriver()->get(self::PREFIX . self::LAST_MODE), true))
        );

        $i = 2;
        while ($data = json_decode($this->getDriver()->get(self::PREFIX . $i), true)) {
            $history[$i] = new MaintenanceState($data);
            $i++;
        }
        return $history;
    }