You may refer below on the steps to perform the kernel update:

Task 1: For Debian/Ubuntu

Step 1: Update and upgrade your packages using apt-get:
#apt-get update && sudo apt-get dist-upgrade

Step 2: You’ll need to reboot your server to apply the changes: –

Task 2: For CentOS/Fedora

Step 1: You can initiate a full yum update using the below command:
#yum update
Just update the kernel packages:
#yum update “kernel*”

Step 2: You’ll need to reboot your server to apply the changes:

Step 3: To verify that you run the update correctly, inside your SSH, run the following command to check: –

cat /etc/redhat-release
uname -r   

Task 3: For Windows OS

Step 1: Click on the Start button

Step 2: Type and enter Windows Update Settings

Step 3: Select Check for updates.

Step 4: Finally, select Install.

Additional Information

What is Kernel?

The kernel is the central module of a server OS. The core that provides basic services for all other parts of the operating system.

In simplified terms, it’s the part of the OS that let applications talk to the hardware and vice-versa.  For example, a spreadsheet app can’t talk to your CPU on its own.  To do that, it goes through the OS and kernel.

Why you need to update kernel?

It is a good practice to always update your OS kernel. By doing it, your OS will have latest security fixes, stability improvements, updated drivers, increased speed and will enjoy any new kernel functions that being provided by the OS manufacturer.

Further to that, due to the current bug of Meltdown and Spectre exploit processor vulnerabilities which allow programs to steal data that currently processed on the computer. The kernel update is necessary as to reduce the risk.