def METHOD_NAME(self, serialized: str, filename: str) -> Tuple[List[str], List[str]]:
    """
    Upgrades container stacks to have the new version number.
    Upgrades container stacks for FLSun Racer to change their profiles.
    :param serialized: The original contents of the container stack.
    :param filename: The file name of the container stack.
    :return: A list of file names, and a list of the new contents for those
    files.
    """
    parser = configparser.ConfigParser(interpolation = None)
    parser.read_string(serialized)
    # Update setting version number.
    if "metadata" not in parser:
        parser["metadata"] = {}
    parser["metadata"]["setting_version"] = "19"
    # Change renamed profiles.
    if "containers" in parser:
        definition_id = parser["containers"].get("7")
        if definition_id == "flsun_sr":
            if parser["metadata"].get("type", "machine") == "machine":  # Only global stacks.
                old_quality = parser["containers"].get("3")
                new_quality = self._flsun_profile_mapping.get(old_quality, "flsun_sr_normal")
                parser["containers"]["3"] = new_quality
    result = io.StringIO()
    parser.write(result)
    return [filename], [result.getvalue()]