This chapter describes upgrade and downgrade of &fml8;. See on the upgrade from &fml4; to &fml8;. Install again. After &fml8; installation, rewrite fml_version line in /usr/local/etc/fml/main.cf to switch fml to the version installed now. Just when the file is saved, fml is changed to the new version. No need to install. Edit /usr/local/etc/fml/main.cf to back the fml_version to the previous one. Just when the file is saved, fml is changed to the new version.