More and more tacx riders who were still using an old version of the software the tacx trainer software 1 2 or 3 or the fortius or i magic software are switching to the new tacx trainer software 4 the tts 4 which also works on the older models of the tacx trainers is a world of difference from the tts 3 and the earlier versions the tts 4 has undergone a metamorphosis with the development of beautifully designed vr terrains that are extremely lifelike such as italian hills and an am