Debian install latest kernel and remove old kernel

Edwardon

Environment: Debian 10 buster 64bit
Apt version: Sid or Unstable

Step 1

Switch apt channel to unstable *recommended
Check current kernel version: 

hostnamectl 
lsb_release -a

Do apt search latest kernel with following command

apt search linux-image-5.6
// Must choose with singed

Step 2

Do apt install

apt install linux-headers-5.6.0-2-amd64 linux-headers-5.6.0-2-common

To list all installed Linux kernel images, type the following dpkg command: dpkg --list | egrep -i --color 'linux-image|linux-headers'

uname -mrs
uname -a

Step 3

Delete unwanted and unused kernel images

dpkg --list | egrep -i --color 'linux-image|linux-headers'
rc: It means package is in remove/deinstall state and only config file exists.
ii: It means package is in install state and it is 100% installed on the system.

You can remove kernel images one by one using the following apt-get command or apt command syntax

apt-get --purge remove linux-image-4.19.0-6-amd64 linux-headers-5.4.0-4-amd64 linux-headers-5.6.0-1-amd64