def convert_conf_for_unreachable(params):
        """
        The 'u' state for UNREACHABLE has been rewritten in 'x' in:
        * flap_detection_options
        * notification_options
        * snapshot_criteria

        So convert value from config file to keep compatibility with Nagios

        :param params: parameters of the host before put in properties
        :type params: dict
        :return: None
        """
        if params is None:
            return

        for prop in ['flap_detection_options', 'notification_options',
                     'snapshot_criteria', 'stalking_options']:
            if prop in params:
                params[prop] = [p.replace('u', 'x') for p in params[prop]]

        if 'initial_state' in params and \
                (params['initial_state'] == 'u' or params['initial_state'] == ['u']):
            params['initial_state'] = 'x'

        if 'freshness_state' in params and \
                (params['freshness_state'] == 'u' or params['freshness_state'] == ['u']):
            params['freshness_state'] = 'x'
The 'u' state for UNREACHABLE has been rewritten in 'x' in:
        * flap_detection_options
        * notification_options
        * snapshot_criteria

        So convert value from config file to keep compatibility with Nagios

        :param params: parameters of the host before put in properties
        :type params: dict
        :return: None