To convert an old Gramps XML file you could use VirtualBox or Vmware and the old lgenealogy images from: http://ftp.gwdg.de/pub/linux/gramps/
Gesellschaft für wissenschaftliche Datenverarbeitung mbH [Mit Beschrnkter Haftung] Göttingen
(gwdg.de or Society for scientific data processing mbH [with limited liability] in the university city of Göttingen in Goettingen district, Lower Saxony, Germany)
So it may be better to replace the note with a link to this page, and maybe add the German FTP site to that.
Note: When I tested things, it looked like the ISO for version 3 was invalid somehow. Windows complained when I tried to open it in explorer, which should normally mount it as an extra drive, and VirtualBox didn’t recognize it as bootable. I think that it had problems with version 2 too.
Version 4 looked OK, but when I tried the GRDB files sent by Willem, Gramps 3.0.1 told me that there was an error with that file, without further explanation.