I currently have OS 10.6 want to upgrade OS
It looks like you can use CS4 with Mavericks according to Adobe's site.


  Is Adobe aware of any major issues, bugs, or odd user experiences when
  using CS5, CS4, or CS3 products with Mac OS X Mavericks (10.9)?
  
  Yes, Adobe Drive could cause the opening or saving of files to take
  longer. See Files open, save slowly for more information.