Depends on the controller version. I can't think of any reason it would not work with something like 3.42.020. I know for a fact that the DYNA1000 series interface (our older MP1000 controller) WILL work with new versions of MACH. I think the reason you got that answer may be because they never took the time to try it. It is possible their later 4000 (and 6000) series controllers would not work with later versions but it would only be if there were some really strange links.
If you have one of the 1000 series contact me and I can help you upgrade the software. The same MACH profile should work.