Even in this new version is not possible to have multiple services running at the same time...
Yes, you can, except in some situations when the same space would be used, so there would be an obvious conflict.
for example to use catering services you should wait until all baggage and cargo has been de loaded from the airplane...I
That's the situation. How else would you imagine it would work in reality, when the rear loader takes exactly the same space of the rear catering ?
is there a way to recover last versions of gsx??
I really don't understand you: you are really saying you would rather have the old version, when you could NOT have simultaneous services under ANY circumstances, as if it was supposedly "better" than the current one, when you can, except in a few cases ? I really don't understand your logic.
How can i get old versions from gsx level 2?
You can't. The simultaneous services was a feature requested by so many users, for so much time, so it won't be removed. Of course, you are not forced to use it so, just don't, and pretend there are no simultaneous services, as it used to be.