Where do I download HikaShop USPS plugin?

I purchased HikaShop Essential today and need to install and activate the USPS plugin. I see people talking about it in this forum but don't see where to download it. I also found this www.ostraining.com/blog/joomla/hikashop-usps-shipping-module/ but the referenced HikaShop url results in a 404 error.

Thanks in advance.