title: Prism 6 compatibility with older versions
body: <p>I have a solution with a main project that uses Prism 5 (WPF). This solution also contains many more projects that are Prism modules.</p>
  
  <p>Now I have to create a new module, and I wonder if I can use Prism 6 only in that module, and it will be compatible with Prism 5 main project, or if I need to continue with Prism 5 in all the modules (or upgrade the entire solution to Prism 6, what is a really big work).</p>
  
  <p>Thank you</p>