This is the second release in a new development branch. This branch should be relatively short lived and will be followed up with the next stable branch, 2.2. It should be backward compatible with rdflib 2.0. I'd like to thank all of you who reported backward compatibility related bugs. And those who submitted patches.
See also: Change Log, License, Credits
Please refer to the documentation for information about rdflib which includes documentation on installing rdflib.