Just to follow through, I installed Fedora F24 on this new Dell E7470 and after dnf upgrade everything works. Originally the Fedora Live testdrive did not work completely (wireless choked and the external HDMI connection would hang the machine) but after installing to disk and updating (kernel when from 4.5 to 4.8) everything just worked. External display was recognised correctly and it installed my printer and printed a test page no problem. So Dell E7470 works great with F24.