# File lib/nanoc3/cli/commands/update.rb, line 19
    def long_desc
      'Update the data stored by the data source to a newer format. The ' +
      'format in which data is stored can change between releases, and ' +
      'even though backward compatibility is usually preserved, it is ' +
      'often a good idea to store the site data in a newer format so newer ' +
      'features can be taken advantage of.' +
      "\n" +
      'This command will change data, and it is therefore recommended to ' +
      'make a backup in case something goes wrong.'
    end