I was following the steps from here (Mail-in-a-Box version v0.40 and moving to Ubuntu 18.04) and was having great luck until I got past restoring backups and re-running mailinabox setup - the last step.
That’s where I hit this:
Mail-in-a-Box Version: v0.42b Updating system packages... Installing system packages... Initializing system random number generator... Firewall is active and enabled on system startup Installing nsd (DNS server)... Installing Postfix (SMTP server)... Installing Dovecot (IMAP server)... Installing OpenDKIM/OpenDMARC... Installing SpamAssassin... Installing Nginx (web server)... Installing Roundcube (webmail)... Installing Nextcloud (contacts/calendar)... Nextcloud or one of the apps require upgrade - only a limited number of commands are available You may use your browser or the occ upgrade command to do the upgrade Set log level to debug Exception: Updates between multiple major versions and downgrades are unsupported. Update failed Maintenance mode is kept active Reset log level
Now my server is completely jacked up and not working properly. Any advice before I restore my old server and go back to .30?