For Version 3.3 and higher
From the introduction:
This guide is meant to provide an overview of the core Nucleus rules and character creation for new players. It is
delibratly brief, for a more detailed overview see [the full rule book].
The "Version 4" release of this product supported the last few releases of the Version 3 rules (Versions 3.3, 3.4, and 3.5) as well as the release of the Version 4 rules.