Why do you think you need to downgrade NI-VISA? Does something not work? Have you tried anything?
While you indeed usually need to have a NI driver version that is not more than 3 years higher than the LabVIEW IDE you are using, that is somewhat less of a program for NI-VISA. First most NI VISA functionality in LabVIEW is built in, so there are not a lot of VIs that an NI VISA installer could add to your LabVIEW installation. Maybe the example VIs, but I'm not even sure about that.
Second, the NI-VISA API itself has been very stable over many years and there is little reason to believe that you would run into compatibility issues with a bigger version difference.
Basically on the development system where you run the LabVIEW IDE, you should make sure that the versions do not differ to much, but on remote systems where you only intend to execute built applications, almost every version of VISA would work, but it is always a good idea to use at least the same version or newer as you used to develop/built your program.