your problem isn't in versions, it in your settings. Using the default Ultra setting will do nothing but add in dozens of features you may not need. click the user box under ultra and carefully think of what you need and dont need in your render settings and select them one by one or not at all. then you need to go into the textures for the plants you are using and go into the AA settings themselves. I don't know why Eon hasn't setup some default animation settings for plants yet, they really need to since its one of the biggest issues still in the program. Here's a good thread in which we've all added ideas and workarounds to animation flickering on the C3D site over the years.
Keep one thing in mind, the default render settings they give you are just that default. Are you rendering a default scene? Not every scene you create will require many of the features they provided in these profiles. While the result may look good, you might and most likely will find you can get a very good render if not better and in shorters times not using the presets.