Can I just buy a new plug-in from MiniDSP?

Not sure how this works. Bought a used MiniDSP 2x4, supposedly with software. Turns out the software is from 2018 and hence does not run without Flash, and the owner does not have the MiniDSP account data.

Can I just register with MiniDSP and buy a plug-in for $10 even if I don't have the original paperwork that came with the box?