Nick J. yeah a lot has changed in the last couple years but the biggest is the style guide builder. With this new project that you are talking about - are you trying to use the figma plugin? If so, that might not be possible without creating a new project from the latest figma kit.
However, if you are just trying to get the latest components into an existing project, you could duplicate the figma kit and make it a library and bring it into that project but you'd still have to assign variables to it.
The biggest issue with older versions is the lack of support for variables. And the lack of features within these apps to sync or retrofit variables.