Now I understand your question!
As Dieter says: the dispaly automatically ajusts to the light (brightness) of the surrounding. If you want to force the adaption you have got to hold it into the sun for a few seconds.
With the ProfiTX you can adjust the contrast manually - and only this way. The old mc4000 has had a menue item for the contrast adjustment - for the even older mc3030 I am not sure, I have to get out the transmitter to find out.
You are right, we are now in 2019. But as always with technical devices: the moment they are on the market they are technically outdated. In the run of the development (and that might be years) of a new tranmitter there always is a point in time where changes are almost impssible. And don't try to compare with our mobiles - there is a new generation almost every year. We are too spoilt!
By the way: monochrom display have their advantages!