1) Backup and restore with ANY web site software (arguably any softare at all) requires that the restore have the same exact version of the code that the original system had. Admin screens have this information in the bottom left corner.
2) The Red "wrong version" stems from the single expected code line entry in /etc/astguiclient.conf (however: Changing this value in no way invalidates #1 above!)
3) After you restore onto the Emergency server: You have to either cause it to have the same IP address as the original server (which requires taking the original server offline, they can't both have the same IP address) or running the IP Update script mentioned in the login splash screen using the OLD DB server's IP as OLD and the NEW DB server's IP as NEW. After running this script, you will need to reboot unless there are no services or screens running on either DB server (old or new).
4) If the new server will have a new IP, I hope it's obvious to you that all the other servers in the cluster must be informed of the new IP, and rebooted to take effect systemwide on each server.
5) You may also want to have a look at creating a Replication/Report server which can technically double as your emergency DB server (and should not incur much loss at all in case of failure, mere seconds in fact if properly built).
6) You must always post your Vicidial Version With Build when requesting support on this forum. You missed the Build
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and your version isn't searchable (so nobody with your exact system will land on your posts and possibly be helped by any bugs you uncover that are Version Related). It's a requirement to post this every time. It helps others, seriously. You should also include your installation method (which is more than just Vicibox 8, it would be 8.X.X with real numbers instead of Xs).