Restore a backup or a previous version? If you updated the hub and you believe it has a negative impact on your system, then "Restore Previous Version" from Diagnostic Tool.
If you deleted your favorite app or driver, then restore a backup from hub's web interface >> Backup and Restore.
Regularly download a current backup from your hub to a safe place, (NAS, USB stick, cloud storage, etc.), in case you want to be able to restore a backup more than a five days old, or in case your hub dies/has some sort of DB corruption and you have to start over.
I recently did this using a backup from a C-5 and put it on a C-7. In my case the C-5 was a HubConnect Server Hub in my Development set... I didn't have any Z-Devices on it. The Z-Radios are disabled. But the backup loaded without a problem AND the HubConnect Remote hubs connected right up. I spent more time fixing up DHCP/DNS to deal with the symbolic name change that it took to swap hubs.