The failover IP can be switched from one server to another in a few seconds.
Therefore, a failover IP allows your hosting services to operate without any interruption and helps you overcome hardware failure issues, system overruns and all kinds of infrastructure problems. In order to take full advantage of the failover IP's power, your hosting services must be configured with the failover IP (as opposed to the server's static IP).
So if you switch the failover IP from one server to another, you keep the entire configuration linked to that failover IP. You are responsible for copying your projects and configuration files from one server to the other.
Since the configuration files are linked to the failover IP, and therefore the data and configurations remain the same, everything will keep working once you have switched the failover IP to the new server.
You don't need to reconfigure all your projects with the static IP of your new server.