Referring to the 24.04 experience: 24.04.0 and 24.04.1 both used the GA kernel (6.8), and starting from 24.04.2, the default ISO switched to HWE (inherited from 24.10’s 6.11).
I’m wondering if 26.04 follows the same pattern?
· 26.04.1: default GA (Linux 7.0)
· 26.04.2: default switches to HWE (inherited from 26.10)
Also, if I install GA from .0 and do a normal apt upgrade all the way to .2, will it automatically become HWE? Or do I have to manually install linux-generic-hwe-26.04?
Thanks.
The GA & HWE kernels are in different packages, and your install media dictates what kernel [package] is installed.
The current GA & HWE kernels can be seen via a [rmadison] package query
linux-generic | 7.0.0-14.14 | resolute | amd64, amd64v3, arm64, armhf, ppc64el, s390x
linux-generic | 7.0.0-14.14.2 | resolute | riscv64
linux-generic | 7.0.0-22.22 | resolute-security | amd64, amd64v3, arm64, armhf, ppc64el, s390x
linux-generic | 7.0.0-22.22 | resolute-updates | amd64, amd64v3, arm64, armhf, ppc64el, s390x
linux-generic | 7.0.0-22.22.1 | resolute-security | riscv64
linux-generic | 7.0.0-22.22.1 | resolute-updates | riscv64
linux-generic | 7.0.0-26.26 | resolute-proposed | amd64, amd64v3, arm64, armhf, ppc64el, s390x
linux-generic-hwe-26.04 | 7.0.0-14.14 | resolute | amd64, amd64v3, arm64, armhf, ppc64el, s390x
linux-generic-hwe-26.04 | 7.0.0-22.22 | resolute-security | amd64, amd64v3, arm64, armhf, ppc64el, s390x
linux-generic-hwe-26.04 | 7.0.0-22.22 | resolute-updates | amd64, amd64v3, arm64, armhf, ppc64el, s390x
linux-generic-hwe-26.04 | 7.0.0-26.26 | resolute-proposed | amd64, amd64v3, arm64, armhf, ppc64el, s390x
The resolute shows the ISO or released install media; where 7.0.0-14.14 is in both the linux-generic and linux-generic-hwe-24.04 packages; thus both are for now using 7.0; but if you’re using the HWE package that will change in the future; where the GA or linux-generic kernel package will remain using the 7.0 kernel.
For more, I’d recommend scanning Kernel/LTSEnablementStack - Ubuntu Wiki where you may note there is nothing preventing both linux-generic and the linux-generic-hwe-26.04 from being installed on the same system; in switching it suggests testing it before you remove the ‘unwanted’ package(s)… Do note some closed source kernel modules (eg. some nVIDIA) can prevent multiple kernel stack co-existing on an install.
There is also this tidbit on the HWE page:
Desktop installations of 24.04 default to tracking the HWE stack.
But I must admit that I’ve never really seen it, because I either do the “install once, upgrade forever” routine or I install by other means than the Desktop installer.
From my understanding, HWE is meant to enable installations on newer Hardware than the original GA kernel at the release date supported, so the point releases default to the HWE stack, whereas, I reckon, the original release just uses and tracks the GA kernel; if it installs, the hardware is obviously supported so no need to risk regressions on such systems.
The only way to know for sure is to check if linux-generic-hwe-26.04 is installed on an installation of 26.04(.0) made by the Desktop installer.
As hinted at by @guiverc there is nothing stopping you from installing the HWE metapackage manually. I do that because I like the perks of newer kernel versions. I did have some regressions too, though, so it’s not all roses — to be fair, I might have been tracking HWE-edge at the time.
I’ll add a little more.
Whilst Ubuntu Server & Desktop have changed kernel stack defaults over recent years (Desktop at 20.04, and Server at 26.04), the Ubuntu Desktop flavors still follow the pattern of Ubuntu 18.04 LTS Desktop in the Kernel/LTSEnablementStack - Ubuntu Wiki I provided; thus both 26.04 & 26.04.1 ISOs will include the GA kernel, with the HWE kernel package on 26.04.2 & later media.
This is what you describe, and has been the same for flavors for over a decade (beyond my involvement in the Ubuntu project anyway).
Small extra check: after an install from .0/.1 media I would look at the metapackage, not only `uname -r`. If the system has `linux-generic` installed and not `linux-generic-hwe-26.04`, normal apt upgrades should keep it on the GA track. It only moves to HWE if the HWE metapackage is installed (by the installer/media choice, or manually later).
So for an existing GA install, I would not expect the .2 upgrade itself to silently swap tracks; verify with `apt policy linux-generic linux-generic-hwe-26.04` before changing anything.
Turns out, I was wrong. I’ve finally come around to actually install a VM using the official vanilla Desktop installer and linux-generic-hwe-26.04 is installed from day one.
Seems like folks might be thinking this is complicated. It’s not.
The pattern is simple:
Both kernel tracks are fully supported in all releases of Ubuntu.
You can change between GA and HWE anytime by using apt. Most folks never need to change.
The GA and HWE kernel versions will always match during the first months of an LTS cycle. That confuses some folks who think it means their system is switching tracks automatically. No, it’s two tracks designed to start together, then to diverge. Your system stays on one track unless you change it.
Example: If you install Ubuntu Server, you get the GA kernel track.
Example: If you install Ubuntu Desktop, you get the HWE kernel track.
Ubuntu 26.04 is expected to follow the same pattern as previous Ubuntu LTS releases.
The GA and HWE kernels are separate kernel tracks. Historically, .0 and .1 releases use the GA kernel, while .2 introduces the first HWE stack based on the corresponding interim release.
Following Ubuntu’s established rolling HWE model:
As for upgrades, a normal apt upgrade does not automatically move a system from the GA track to the HWE track. The installed kernel meta-package determines which track you follow.
If your system is using linux-generic, it will remain on the GA kernel. To switch to HWE, you would need the corresponding linux-generic-hwe-26.04 meta-package.
Canonical has not yet published an explicit statement confirming the exact HWE transition point for 26.04, so this is based on the established behavior of previous LTS releases.
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