public static function checkComposerVersion(Event $event) {
    $composer = $event->getComposer();
    $io = $event->getIO();

    $version = $composer::VERSION;

    // If Composer is installed through git we have no easy way to determine if
    // it is new enough, just display a warning.
    if ($version === '@package_version@') {
      $io->writeError('<warning>You are running a development version of Composer. If you experience problems, please update Composer to the latest stable version.</warning>');
    }
    elseif (Comparator::lessThan($version, '1.0.0')) {
      $io->writeError('<error>UpMembership requires Composer version 1.0.0 or higher. Please update your Composer before continuing</error>.');
      exit(1);
    }
  }