I think KOffice will be called Calligra in the future. When Calligra is released in a final version it will replace Koffice if I understand it correct.
"The Calligra project, being part of the KDE community, is dedicated to producing Free Software, therefor you can download and install Calligra Suite in most cases free of charge. While the Calligra project only provides source code, it is easily installable through the package manager of many linux distributions, FreeBSD. There is also preliminary support on Mac OS X and Windows. No release of Calligra Suite has been made so far
, but two versions of KOffice are currently available"