When I started running FAH, the version of the command line client available was the 502 version. 504 was still a beta. Now 504 is the current release. Do I have to run the -config option on the 502 client to uninstall it first as a service, or will the 504 version install over the top of the 502 version?
Just to be safe I would uninstall the 502 client and then reinstall the 504 client. You can backup the queue.dat and /work folders to keep your current work unit, I’m sure the queue is compatible with the later client.
uninstall 502 using -configonly or you end up with a naff service left over. Or at least I remember I did, whether that’s 100% is still to be seen, only had the one 
so far today 
DT.