It is always a great idea to do a backup before performing an upgrade.
a) Virtual Machine Snapshot
The best possible option is to take a Virtual Machine snapshot. This allows for a quick and complete restore if the dbFront install fails for any reason.
b) Regular Server Backup
Regular server backups are a good option, but restoring a server backup can be a complex task.
c) Selective Folder Backup
Assuming a default install, the dbFront folders that should be backed up are:
- Service Folder: c:\program files(x86)\dbfront
- Website Folder: c:\inetpub\dbfront
- Data / Settings: c:\data\dbFront
To manually backup your IIS settings see: Backup and Migrate IIS Configuration
Upgrading dbFront on a Default Install
To upgrade dbFront you should be able to just run the dbFront installer and do a regular install and it will upgrade the service and the website files without damaging your setup. But just in case you should run a backup first.
You only need a custom install if you manually installed dbFront initially.