Install Rhino 4 + Tsplines 1.5

I have a little issue.

I want to run Rhinoceros 4 on a new computer since those are the licenses i have. Think its Tsplines 1.5 version which wont run on newer Rhino is what ive heard…

Whats the latest version of OS i could run theese on?
Can i do Win7? in case not - why?

Rhino 4 should run on Win7 fine. --Mitch