FYI it's harder to get a copy of cura 15.X these days so I'm hosting it here (sorry, I only have the windows version): Cura 15.04.06 for windows   It doesn't have nearly as many features as the latest cura and doesn't support UM3 or newer printers and it supports dual color printers but not second-extruder-support.  But it works very well for 90% of printers out there and in some cases produces better prints (not sure why).  I usually use the latest Cura but occasionally still use