Actually, it is the other way round - you can safely leave the config.xml from yr previous install, but you *must* replace the default.xbe as that is the new program.
Better yet, rename it to suit your boot-up preference in yr bios and put in C:. It's worth it, best version yet!
edit: noticed yr sig, so you are running UnleashX as boot-up dash already right?
As I use 4983 also, which boots avalaunch.xbe first, I rename unleash as avalaunch.xbe, and leave Evox as evoxdash.xbe as "back-up" for trainers etc.