code: public static synchronized boolean isUpdate(Selector selector) {
  		ensureLoaded();
  		Set<String> uniques = new HashSet<String>();
  		for (VersionHistoryEntry entry : versionHistoryEntries) {
  			switch (selector) {
  				case version_name:
  					uniques.add(entry.getVersionName());
  					break;
  				case version_code:
  					uniques.add(String.valueOf(entry.getVersionCode()));
  					break;
  				default:
  					break;
  			}
  		}
  		return uniques.size() > 1;
  	}
docs: Returns true if the current version or build is not the first version or build that we have seen. Basically, it just
  looks for two or more versions or builds.
  
  @param selector - The type of version entry we are looking for: version, or build.
  @return True if there are records with more than one version or build, depending on the value of selector.