code: @Nullable
  	private static String retrieveRemoteVersion(@Nonnull final URL url, @Nonnull final Charset charset) throws IOException {
  		final InputStream stream = url.openStream();
  		final InputStreamReader reader = new InputStreamReader(stream, charset);
  		final LineNumberReader lnr = new LineNumberReader(reader);
  		final String line = lnr.readLine();
  		lnr.close();
  		reader.close();
  		stream.close();
  		return line;
  	}
docs: Reads the current User-Agent data version from <a
  href="http://data.udger.com">http://data.udger.com</a>.
  
  @param url
  a URL which the version information can be loaded
  @return a version string or {@code null}
  @throws IOException
  if an I/O exception occurs