Sounds crazy?
Probably is, but I would like to convert old PCX5 files to / from GPX. V6.5 was the earliest version to read / write GPX, and V6.8.0 the last version to deal with the old PCX5 type files, so anything in between those two should do the trick.
I currently have something like V3 & V15, neither of which will handle both.
Does anyone have an old disc lurking in a corner for a long gone handheld that they don't need any more? If so how much do you want for it?