The currently available Linux kernel has the version: 6.12.6 (found: 2024-12-20). Source: www.kernel.org. The Linux distributions, as an example Debian or Ubuntu used new kernel versions only with some delay, accordingly the used kernel versions are usually somewhat older. Which kernel is active on a Linux system can be read out with the following command:

Display the currently used kernel

To do this, enter the following command in the terminal:

uname -a

show available kernel versions

On Debian or Ubuntu, available kernel versions can be displayed as follows:

sudo apt-get update
sudo apt-cache search linux-image

Installing a newer kernel bersion

To install a newer kernel version, the following command can be used:

sudo apt-get install linux-image-4.17.0-0.bpo.1-amd64

At this point it should be mentioned that there is typically no reason to change the kernel unless the new kernel solves a specific hardware problem.

Default kernel for booting

If multiple kernel versions are installed, they can be selected at boot time.

Responsible for this is the bootloader. The bootloader configuration can be customized in the /boot/grub/grub.cfg file.

sudo nano /boot/grub/grub.cfg

By default, the first "menuentry" block is started. By changing the order of the "menuentry", a specific kernel version can be placed at the top of the list and thus started as default.

The boot parameters can be customized within the menuentry block:

linux /boot/vmlinuz-4.15.0-0.bpo.2-amd64 root=UUID=???xx-???x.. ro quiet splash i915.enable_psr=0