nvidia304 hangs with fc23 kernel

Yesterday I ran dnf system upgrade from fc22 to fc23. It all seemed very smooth (4185 packages) until it rebooted to emergency mode. After repairs by fsck it runs happily under 4.4.13-200.fc22 but just hangs with a black screen and a flashing cursor with 4.5.7-200.fc23 yumex-dnf seems inconsistent in reporting the state of the fc23 kernel, akmod-nvidia-304xx and kmod. Now it is showing them as uninstalled, with 'Error(s) in search for dependencies' if I try to install the current 4.5.7-200.fc23 An attempt to install 4.2.3-300.fc23 is apparently seen as a downgrade of 4.4.12-200.fc22 (not the running kernel) and is then rejected as conflicting. I suppose I can continue as is until the next kernel appears - but a fix would be better :-) I was able to rpmbuild --rebuild the rpmfusion mythtv-0.28-3.fc24 srpm, and have it running now. Strangely, an attempt to update my earlier fc22 build of mythtv master failed with qt5 problems. John P