Configuration files are used to store your customizations. The file format of configuration files has changed for version 3.5, but Source Insight can still read the 2.x format files. In addition, the file extension has been changed from .CF to .CF3.
To load your old configuration file, use the Options > Load Configuration command. Click the Load button and navigate to the directory where Source Insight version 2.x is installed. You should see files with .CF extensions. The main global configuration file is named global.cf in version 2.x. Select that file and click OK. The old configuration file will be loaded and saved automatically to global.cf3 – the new name of the global configuration file.