Unfortunately, MyThreadBox software doesn't exist anymore. I've checked the official website, but a generic page is displayed instead for when the domain expires. That means the software is discontinued as well and the version that you have is actually the latest one available.
I've found out that iCanHelpSew website still sells this product. Contact them through the following page to obtain additional details: http://www.icanhelpsew.com/mythreadbox.html
