20160908:
  AFFECTS: security/letsencrypt.sh
  AUTHOR: sascha@root-login.org

  The config filename has been changed upstream from "config.sh"
  to "config". You'll have to rename your current config file!
  Also the default WELLKNOWN location has been changed to
  %%PREFIX%%/www/letsencrypt (upstream: /var/www/letsencrypt).
  To use the old location you'll have to modify your config
  file!