Upgrade instructions if you already have version 1.0 running:
1. Extract the zip file and open the Validate.php that fits to your ubb.threads version.
2. Adjust the path to the logfile like you did during the inital installation
3. Optionally change the settings (see instructions.txt for a list of configuration options)
4. Upload the new Validate.php to your server
You don't need to alter ubbt.inc.php during the upgrade.
It's a good idea to delete the logfile to start fresh before doing the upgrade.