async checkForUpdates(channel, fromVersion) {
    // awaits the first refresh
    const latest = await this.getLatest(channel);
    if (!latest) {
      return;
    }
    if (process.env.UPDATE_CHECKER_ALLOW_DOWNGRADES === 'true') {
      if (fromVersion !== latest.version) {
        return latest;
      }
    }
    if (semver.lt(fromVersion, latest.version)) {
      return latest;
    }
  }