Hi Tatopitta!
Well, it all depends. If they are connected to the network and the form template is on a server then it should pull down the most recent. Obviously, if someone does something sneaky like going into Tools->Advanced and manually resetting the version, then thigs won't work so well. Please check the version info in the saved XML files for the users that have the old version and compare to the version number saved in the XML file for the users with seemingly new forms. Then, check those against the form template.
Patrick Halstead [InfoPath MVP]
InfoPath Dev Seattle
Patrick Halstead
Project Manager at Qdabra