Debian Buster: linux-image-amd64 kept back

Perhaps a simple question, perhaps a stupid question, but I can't find an answer...

Whenever I do

apt-get update
apt-get upgrade

I get

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

Sooooo, what exactly is happening here?

Sooooo, what exactly is happening here?

The apt-get upgrade does not add new packages. The linux-image-amd64 is a meta package that often depends on installing a new package that is the newest version of the kernel.

A new package is used whenever the ABI changes, this can be very important for anyone with any locally compiled modules, that aren't managed by DKMS or something.

Ref: https://wiki.debian.org/DebianKernelABIChanges

Occasionally, and often due to a security issue, a change is accepted into a kernel package that changes its ABI. The ABI change is represented by a change in the ABI version portion of the linux-image package name.

Anyway, if you want to upgrade to the latest kernel use apt-get dist-upgrade.

I'm just copying the relevant parts of this complete answer, go check it out!:

Sooooo, what exactly is happening here?

If the dependencies have changed on one of the packages you have installed so that a new package must be installed to perform the upgrade then that will be listed as "kept-back".

How to install those packages properly:

sudo apt-get --with-new-pkgs upgrade