Linux distributions will provide a kernel and updates for it automatically. These typically aren't the latest version of the kernel. You may want to use a newer kernel to benefit from new features or performance enhancements.
Please note: Using a kernel that hasn't been tested by your Linux distribution may cause issues.
1 Check your current kernel version
To find out what kernel version you are using, open the GNOME Launcher and click on Terminal. Type in the below command:
uname -r
This will output on screen your current running kernel version.
4.15.0-39-generic
2 Download the new kernel
Newer versions of the kernel for Ubuntu, Linux Mint, elementary OS and other deriviatives can be downloaded from: http://kernel.ubuntu.com/~kernel-ppa/mainline/
The current latest stable release at the time of writing this is 4.19.5
Please note: Any kernel version that is appended with rc is a release canditate - these are not stable.
Once you click on the kernel version, you will need to download 3 files under the section: Build for amd64 succeeded:
linux-headers-4.19.5-0419054.19.5-041905.201811271131_all.deb
linux-image-unsigned-4.19.5-041905-generic4.19.5-041905.201811271131_amd64.deb
linux-modules-4.19.5-041905-generic4.19.5-041905.201811271131_amd64.deb
3 Install the downloaded files
From the terminal, navigate to your downloads folder by typing:
cd Downloads/
And then, use the below command to install all 3 files:
sudo dpkg -i *.deb
4 Reboot your laptop
Reboot the machine for the new kernel changes to take effect. You can use the same command to verify the new kernel is being used:
uname -r
5 Removing kernels
If you would like to remove a kernel, you can use the below command replacing the version number with the version number of the kernel you would like to remove:
sudo apt remove linux-4.19.5
After this command completes, reboot to apply the change.