The iterative approach and versioned releases are closely related; in fact, versioned releases are one instance of the iterative approach. The approach, however, includes not only releases and release candidates, but all milestones and deliverables within the project. In this sense, you can think of the process milestones as "spirals within spirals" of successive refinement, as illustrated in the following diagram.
The iterative approach
Between each milestone, the team members build on the draft documents, negotiate the content, and prepare plans for their own teams. The teams work in parallel in this iterative manner.
The concept of versioned releases and "product mindset" are important elements throughout the systems development life cycle because they impact how expectations are set, how decisions are made, and how the entire project is planned and managed.