RSLinx upgrade question

I want to perform a web update of my RSLinx software (I currently have RSLinx Classic Gateway version 2.50). On the Rockwell support site I have the option of downloading RSLinx Single Node, RSLinx OEM, RSLinx Professional, RSLinx Gateway, RSLinx SDK, or RSLinx Enterprise. What's the difference? Do any of these packages include the features of ALL the listed packages?

Thanks.

You will only be eligable to download the version that you have a licence/and support for. (Lite is free)

(Professional) has pretty much everything, but unless you have a valid s/n with support contract you cannot download it.

Thanks. My company purchases the Rockwell Toolkit annually with about 15 licences, so I'll see what I'm able to download.