What changes from 2.0.10 to 2.0.20b broke payment plugin?

[t68]

Hi!
This might be a "Mission Impossible" question, but anyway:
I use a payment service that has a working payment module documented to work with VM versions up to 2.0.1.
But "of course" it wont work with the latest VM version, 2.0.20b.
The support for the service states that they are working on an updated module but cannot give any release date.
Thing is I really want to use this payment module since they offer both payment and a god invoice service. But it feels not so ok to run an old VM version.

So here´s my question:
Could it be possible for me to adjust the code in the payment module to get it working with the latest VM version?
Wishful thinkin´maybe, but who knows, maybe it´s just a minor change that has to be made, like a line of php that has to be altered.

Thank´s for any input on this.

P.S: if someone wants to have a look at the code the module is downloadable here:
https://www.payson.se/integration/moduler/virtuemart