Using Preview Features in Power BI Desktop Report Server Version

I'm currently testing out the functionality of Power BI Report Server, which requires you to download a different version of Power BI Desktop (it's called Power BI Desktop Report Server).  All of my Power BI Desktop reports currently use the "New table and matrix visuals" preview.  

When I try to view these reports using Power BI Report Server, the "preview" table and matrix visualizations are blank.  When I go to the Options menu in Power BI Desktop Report Server, there is no "Preview Features" menu item - so I don't see a way to turn this on.  Is it possible to use preview features with PBI Report Server?