If you would want to change from kernel 2.4.19 to another kernel, yes, you would probably need another display drivermodule. You could perhaps use the binary module for 2.4.19 for another 2.4.x kernel, but this depends.
Running another majorversion (e.g. 2.2 or 2.6): (Nearly) No chances without writing a new display driver or getting another binary from iRex (see
http://forum.irexnet.com/viewtopic.php?t=1569)