code: public SdkUpdater newUpdater() {
      if (version != Version.LATEST) {
        throw new UnsupportedOperationException("Cannot update a fixed version SDK.");
      }
      return SdkUpdater.newUpdater(osInfo.name(), getGcloudPath());
    }
docs: For "LATEST" version SDKs, the client tooling must keep the SDK up-to-date manually, check with
  {@link #isUpToDate()} before using, returns a new updater if sdk is "LATEST", it will throw a
  {@link UnsupportedOperationException} if SDK is a fixed version (fixed versions should never be
  udpated).