To be honest:
You cant endlessly require new O.S. versions for your old keyboard.
Just take a look at the instruments which were presented the same time like the X1!
Is there a new O.S. for the Yamaha PSR8000? Or even the PSR9000? Or the GEM WK8?
Or the Korg i30?
Even the O.S. 4.0 for the SD1 is big exception in keyboard industry and this updateeven was free of charge!
And, by the way: Are you shure, that you have discovered all the possibilities of your
current keyboard?(Doesnt matter if it`s a Ketron or Yamaha or...)
I even know a lot of MS50 owners and they are very satisfied with their instrument.
No one expects KETRON to burn new chips with new features.
It`s our destiny that we are playing a kind of instrument which is always in technological progress, so we have to take care, that we buy an instrument that satisfies us longer then only 1 or 2 years.

But... always better then to play guitar...