I've never had a problem connecting different versions with the sound to light. I notice, however, that older versions seem to have slightly different Mspeed calibrations and wheel rotate speeds, so it may not do exactly the same thing (might not move as far for the same step in the program). I tend to upgrade all of my lights to the most recent versions, however (having an eprom burner makes this easy). so I haven't experienced this in quite a while... i might be remembering incorrectly.
