public boolean versionDiffers() {
    final Boolean cached = myVersionDiffers;
    if (cached != null) {
      return cached;
    }
    try (DataInputStream is = new DataInputStream(new FileInputStream(myVersionFile))) {
      final boolean diff = is.readInt() != VERSION;
      myVersionDiffers = diff;
      return diff;
    }
    catch (FileNotFoundException ignored) {
      return false; // treat it as a new dir
    }
    catch (IOException ex) {
      LOG.info(ex);
    }
    return true;
  }
public boolean versionDiffers()