I dropped my laptop which was all working with Qcad and our network printers. So now have a new one, its Fedora 20 which has the latest Cups 1.7, but I could get no printers in Qcad 3.4.6
Eventually a tweak to add a /etc/printcap generation to the cups config gave me the local printers, but I can not see the printers on the cups v1.1 server. Other apps are working ok. Unfortunately cups does not store network printers locally, so have no idea how my old laptop was working.