Update Manager asking me to update kernel but apt-get upgrade does not?

Solution 1:

That's because apt-get upgrade does not install new packages.

Due to the way the kernel packages are built, every new (bugfix) version of the package actually has a different name. Plus you install a metapackage, which will always depend on the latest kernel.

This has as a sideeffect, that updating the metapackage for the kernel always requires a new package to be installed (the new kernel), which update-manager will happily do for you.

apt-get upgrade however will strictly upgrade packages, and will not install new packages. If you run apt-get upgrade, you will see that the kernel metapackage is being held back (for this reason, though it doesn't give you the reason).

So instead of apt-get upgrade, run apt-get dist-upgrade to update the kernel metapackage and install the latest kernel version.

Solution 2:

In my last login to Ubuntu Server, I suggest to use do-release-upgrade. This may help any version to upgrade to the last version.