Currently there are no plans to replace Exim and Courier support with other MTAs and MDAs. However antivirus and antispam support is on the list.

ajenti-v-ftp-pureftpd package is now available for testing instead of the problematic vsftpd support

Ajenti V now includes PureFTPd plugin (replacement for vsftpd plugin) - ajenti-v-ftp-pureftpd package. Feedback much appreciated!

I see; In case of emergency you can disable authentication in config.json file and fix the settings as Ajenti's root user. However locking yourself out of root account in Ajenti isn't a way to go :)

After enabling OS user sync, log in to the panel as root user, and assign permissions to the users in Configuration section.

Unfortunately while Ajenti V is beta, we only have commit log on https://github.com/Eugeny/ajenti-v/commits