Qubes update stalls with new packages

After waiting hours for Qubes update to update a debian standalone I finally gave up and tried apt-get update && apt-get upgrade without continuing the upgrade. I received the message

The following packages have been kept back: linux-headers-amd64 linux-image-amd64

So I checked apt-get upgrade --with-new-pkgs and verified that apt wants to install new packages.

Is it possible to run Qubes update and also install these new packages? If not, what’s the most secure way to upgrade when packages are being held back?