Hey Andreas,
I saw the below lines in [1], which I had not noticed before:
"recently (2014) the authors of Richardson Lab software formally agreed to drop the condition: "...and (2) any modified versions of the program are also available for free."
So, it seems the problem is solved :)
Moreover, I think I was wrong about the authors. It seems Jane Richardson is the main author[2]. Also, the below email addresses are related to Jane and Micheal Richarsdon, as it is mentioned in [3]:
All of things, that I need to do, is to remove the second condition from Copyright, and add Jane and Micheal email addresses as the upstream's members.
Best Regards,
Mali