After installing the latest KF5 ISO (2014.10.13), I noticed that "update-grub" is missing. Is this intended?

There never has been an "update-grub" in KaOS, a few posts with what to use:

sudo grub-mkconfig -o /boot/grub/grub.cfg

Plus that is not a Kf5 ISO, all kf5 ISOs have that clearly in their name.

is the latest, Oct 13 is a KDE 4 (UEFI) ISO.

Sorry, it was the 2014.10.30 ISO.