Ok, a very kind and trustworthy representative of Valentine Research, Mr. Kaufman, just gave me the reply regarding the new software and it is as I quote here:
"There’s not much difference between 3.851 and what you have. This change has primarily to do with manufacturing convenience.
Of course, we always try to improve the V1 with every change we make, but this one is focused on making the manufacturing process easier. The user-oriented improvements are: a very minor increase in sensitivity, small improvements in false signal rejection, and a minor increase in Euro-mode frequency coverage for Ka band."
Thanks for clarification, Pete!