Yes. The obvious difference, and it's an important difference, is that one of them contains the word “portfolio”. The one mentioned in 5.20 developed in 2012 was a project management framework, so a framework for managing individual projects.
In 5.10 we're talking about a project portfolio management framework, or how you have that view of all of the projects, the whole portfolio of projects that are going on at one time.
It's one thing and is a good practice to have a framework to manage individual projects, but then from an organizational point of view you need a way to manage your portfolio of projects that are all going on at the same time.