Upgrading from Centura to Gupta & Gupta compatibility with .NET

Hi guys,

I would like to know whether it is possible to upgrade a Centura
application to
Gupta.

Question 1)

Is it done seamlessly? Where could I get information about this kind of
upgrade?

Question 2)

Does Gupta integrate with .NET applications? I mean, is it possible to
use .NET
components in Gupta? What about .NET graphical components? Can they be
integrated straight into Gupta? I have heard that there was a
limitation with
Centura. For integrating .NET graphical components into Centura, the
..NET
components had to be able to run into their own separate window because
they
couldn't share the same event handler as the Centura components _
something
like that. So here and there in the Centura application I got, we see
pushbuttons
that invoke .NET executables that run into their own windows, this is
how far
the integration goes. What about Gupta?

Question 3)

Is it possible to develop Gupta code and run it either on
Linux/Windows/mixed
platforms? Do we only need to recompile the code or is there something
else to
be done?

Thank you in advance for your kind help!!!
Sandrine