Backup your current Vallum configuration before updating, as it may be get lost during the update process. The best way do backup it is so save it as custom preset or exporting it to file.
To update from Vallum 1.x please run the provided Vallum 2.0 installer and wait for your Mac to automatically restart. In case of problems updating Vallum please run the Vallum Uninstaller, wait for it to finish and restart your Mac, then reinstall Vallum. Remember to backup your Vallum configuration before uninstalling.