server - Still on previous 4.15 kernel after apt upgrade to 18.04.2

TL;DR

I can't force my ubuntu server, after upgrading to 18.04.2 from 18.04.1, to upgrade the kernel to corresponding 4.18 version.

Historical background

Yesterday I run

sudo apt upgrade

and had a conflict on one of the minor files (I think it was /etc/issue.net). Unfortunately, during solving that conflict I accidentally turned off putty... When I logged back in I had a lock on the apt database. I restarted my server and executed

sudo dpkg --configure -a

Then sudo apt upgrade went fine. After I restarted my server I saw, in the welcome message, that my system got updated but the kernel is still in 4.15 version.

Welcome to Ubuntu 18.04.2 LTS (GNU/Linux 4.15.0-45-generic x86_64)

What I have tried so far

I tried all the solutions I could find on the Internet but none of them helped:

rychu@RychuSRV:~$ sudo apt update
Hit:1 http://ppa.launchpad.net/certbot/certbot/ubuntu bionic InRelease
Hit:2 http://archive.ubuntu.com/ubuntu bionic InRelease
Get:3 http://archive.ubuntu.com/ubuntu bionic-updates InRelease [88.7 kB]
Hit:4 https://download.docker.com/linux/ubuntu bionic InRelease
Get:5 http://security.ubuntu.com/ubuntu bionic-security InRelease [88.7 kB]
Fetched 177 kB in 1s (161 kB/s)
Reading package lists... Done
Building dependency tree
Reading state information... Done
All packages are up to date.
rychu@RychuSRV:~$ sudo apt-get install linux-image-generic
Reading package lists... Done
Building dependency tree
Reading state information... Done
linux-image-generic is already the newest version (4.15.0.45.47).
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
rychu@RychuSRV:~$ sudo apt-get install linux-generic
Reading package lists... Done
Building dependency tree
Reading state information... Done
linux-generic is already the newest version (4.15.0.45.47).
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
rychu@RychuSRV:~$ uname -r && dpkg --get-selections linux
4.15.0-45-generic
linux-base                                      install
linux-firmware                                  install
linux-generic                                   install
linux-headers-4.15.0-45                         install
linux-headers-4.15.0-45-generic                 install
linux-headers-generic                           install
linux-image-4.15.0-23-generic                   deinstall
linux-image-4.15.0-29-generic                   deinstall
linux-image-4.15.0-30-generic                   deinstall
linux-image-4.15.0-32-generic                   deinstall
linux-image-4.15.0-33-generic                   deinstall
linux-image-4.15.0-34-generic                   deinstall
linux-image-4.15.0-36-generic                   deinstall
linux-image-4.15.0-38-generic                   deinstall
linux-image-4.15.0-39-generic                   deinstall
linux-image-4.15.0-42-generic                   deinstall
linux-image-4.15.0-43-generic                   install
linux-image-4.15.0-44-generic                   install
linux-image-4.15.0-45-generic                   install
linux-image-generic                             install
linux-modules-4.15.0-23-generic                 deinstall
linux-modules-4.15.0-29-generic                 deinstall
linux-modules-4.15.0-30-generic                 deinstall
linux-modules-4.15.0-32-generic                 deinstall
linux-modules-4.15.0-33-generic                 deinstall
linux-modules-4.15.0-34-generic                 deinstall
linux-modules-4.15.0-36-generic                 deinstall
linux-modules-4.15.0-38-generic                 deinstall
linux-modules-4.15.0-39-generic                 deinstall
linux-modules-4.15.0-42-generic                 deinstall
linux-modules-4.15.0-43-generic                 install
linux-modules-4.15.0-44-generic                 install
linux-modules-4.15.0-45-generic                 install
linux-modules-extra-4.15.0-23-generic           deinstall
linux-modules-extra-4.15.0-29-generic           deinstall
linux-modules-extra-4.15.0-30-generic           deinstall
linux-modules-extra-4.15.0-32-generic           deinstall
linux-modules-extra-4.15.0-33-generic           deinstall
linux-modules-extra-4.15.0-34-generic           deinstall
linux-modules-extra-4.15.0-36-generic           deinstall
linux-modules-extra-4.15.0-38-generic           deinstall
linux-modules-extra-4.15.0-39-generic           deinstall
linux-modules-extra-4.15.0-42-generic           deinstall
linux-modules-extra-4.15.0-43-generic           install
linux-modules-extra-4.15.0-44-generic           install
linux-modules-extra-4.15.0-45-generic           install
rychu@RychuSRV:~$ sudo update-grub
Sourcing file `/etc/default/grub'
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-4.15.0-45-generic
Found initrd image: /boot/initrd.img-4.15.0-45-generic
Found linux image: /boot/vmlinuz-4.15.0-44-generic
Found initrd image: /boot/initrd.img-4.15.0-44-generic
Found linux image: /boot/vmlinuz-4.15.0-43-generic
Found initrd image: /boot/initrd.img-4.15.0-43-generic
Adding boot menu entry for EFI firmware configuration
done
rychu@RychuSRV:~$ sudo reboot

And...

Welcome to Ubuntu 18.04.2 LTS (GNU/Linux 4.15.0-45-generic x86_64)
rychu@RychuSRV:~$ uname -r
4.15.0-45-generic

I also tried

rychu@RychuSRV:~$ sudo do-release-upgrade
Checking for a new Ubuntu release
There is no development version of an LTS available.
To upgrade to the latest non-LTS develoment release
set Prompt=normal in /etc/update-manager/release-upgrades.

Please help.

You can upgrade kernel and keep it getting upgraded to future point Ubuntu releases by running

sudo apt install linux-generic-hwe-18.04

As for now it will install the 4.18 kernel.