Ubuntu LTS releases have two main kernel stack choices
GA or the general kernel stack
This kernel stack remains the same for the life of the product. For Ubuntu 20.04 LTS it will use the 5.4 kernel.
HWE or hardware enablment stack
This kernel stack will change as the release advances.
At
- 20.04.2 it uses the 5.8 kernel stack from Ubuntu 20.10
- 20.04.3 it uses the 5.11 kernel stack from Ubuntu 21.04
- 20.04.4 it uses the 5.13 kernel stack from Ubuntu 21.10 (20.04 or focal is progressing to 20.04.4 currently with some of the packages already installed)
- 20.04.5 will use the 5.15 kernel stack from Ubuntu 22.04 LTS (the GA stack for 22.04).
See https://wiki.ubuntu.com/Kernel/LTSEnablementStack for details.
Ubuntu Server installs default to the more stable GA stack, but it can be changed at install, and post-install.
Ubuntu Desktop installs default to the HWE stack by default, but can be changed post-install.
Ubuntu flavors can vary depending on media; I'll use Lubuntu 20.04 as example.
- Lubuntu 20.04 & 20.04.1 media defaults to GA kernel stack for new installs
- Lubuntu 20.04.2 & later media defaults to HWE kernel stack for new installs.
Other OEM kernel stacks can also be used for new installs; if the installer detects your hardware as benefiting from an OEM kernel.
You can have both kernel stacks (GA & HWE) installed on a system as well; meaning you'll have more to upgrade (both will get updates), but the bandwidth & disk space used isn't that great; you select at boot (ie. grub
) which you'll use. However do note some closed-source or proprietary video drivers do not allow both stacks to co-exist.
Refer to the provided wiki page how to install/switch installs; eg. to switch from HWE to GA (for Ubuntu Desktop 20.04 LTS) search for "To downgrade from HWE/OEM to GA kernel:"