This question pertains to the transition from Angular V2 to Angular V4.0.0, which was almost ready for release at the time of writing (currently in RC-3). The @Angular/platform-server component has undergone significant changes.
For more information, you can refer to this link:
https://github.com/angular/angular/issues/13822
A portion of Angular Universal's API has been integrated into @angular/Core, while other aspects have been rewritten under the name of @angular/platform-server.
As mentioned by @mikezks in the discussion thread
https://github.com/angular/angular/issues/13822#issuecomment-286742244,
the key function is now renderModuleFactory (which powers server-side rendering).
Therefore, @angular/platfomr-server is now dedicated to server-side rendering in Angular and generating HTML pages within NodeJS.