We’ve tested our plugin with WordPress 3.8+ and we recommend using the latest version of WordPress.
What version of WordPress do I need?
Yes, you can purchase single site license. But right now codecanyon.net does not offer any up-gradation facility. We are selling our plugin exclusively in codecanyon.net . So, we can’t offer such kind of facility too.
But, If you want to use Knowledgebase plugin for multiple sites then you can purchase an extended license from codecanyon.net