PMBOK Fourth Edition was released in 2008. It had five process groups, with nine knowledge areas and 42 processes. The fifth edition was released last year, and while it includes the same five proess groups, there are now 10 knowledge areas and 47 processes.
In the fourth edition, stakeholder management was part of communications management. In the fifth edition, stakeholder management is now its own knowledge area.
One added process is 5.1 Plan Scope Management
This is the process of creating a scope management plan that documents how the project scope will be defined, validated, and controlled. The key benefit of this process is that it provides guidance and direction on how scope will be managed throughout the project.
Let me know if you want to learn about other differences between these two project management guides.
