To find out what the Cast for Now feature does, I recommend launching Horoscope Explorer and looking into the application's help files for the answer. In case the function isn't explained there, you might want to contact the developers directly as they are the most qualified ones to answer your questions.
As far as upgrades go, according to the Software Informer page, 5.2 is the latest version of the application and unfortunately, the official website doesn't offer any information regarding the current version.