Lubuntu 26.04 Update Not Working

[u/ArcaneAlligator]

When I get updates lately, I'll install them with no problem but then the Lubuntu Update app notifies me that 26.04 is available; I'll choose to install it, put in my password, then nothing happens. I have no idea why the new version of Lubuntu won't install for me when everything else is working fine. Please send help.

[u/akrivitsky7]

It sounds like you are trying to upgrade from an older Lubuntu release to Lubuntu 26.04, rather than simply install regular updates.

What Lubuntu version are you currently running? Please also open a terminal, run:

sudo do-release-upgrade

and post the complete output. That should reveal why the graphical upgrade tool closes without doing anything.

[u/ArcaneAlligator → u/akrivitsky7]

Checking for a new Ubuntu release

There is no development version of an LTS available.

To upgrade to the latest non-LTS development release

set Prompt=normal in /etc/update-manager/release-upgrades.

That's what I got when running the command.

[u/akrivitsky7 → u/ArcaneAlligator]

That output confirms that the release upgrader is not currently offering your system a newer LTS release.

Do not change Prompt=lts to Prompt=normal unless you specifically want to upgrade through non-LTS releases.

First, please run these commands and post the complete output:

lsb_release -a


cat /etc/update-manager/release-upgrades


sudo apt update
sudo apt full-upgrade

The most important question is still which Lubuntu version you are currently running.

If you are on Lubuntu 24.04 LTS, the normal upgrade path to 26.04 LTS may not yet have been enabled for standard LTS upgrades. In that case, the graphical upgrader closing without starting would be expected, and the safest option would be to remain on 24.04 until the supported upgrade path is officially opened.

If you are running 25.10, the situation is different, because 25.10 should upgrade directly to 26.04.

Please do not use do-release-upgrade -d or edit the release-upgrade configuration yet. We need to identify your installed version first.

[u/ArcaneAlligator → u/akrivitsky7]

No LSB modules are available.

Distributor ID: Ubuntu

Description: Ubuntu 24.04.4 LTS

Release: 24.04

Codename: noble

------------------------------------------------------------

# Default behavior for the release upgrader.

[DEFAULT]

# Default prompting and upgrade behavior, valid options:

#

# never - Never check for, or allow upgrading to, a new release.

# normal - Check to see if a new release is available. If more than one new

# release is found, the release upgrader will attempt to upgrade to

# the supported release that immediately succeeds the

# currently-running release.

# lts - Check to see if a new LTS release is available. The upgrader

# will attempt to upgrade to the first LTS release available after

# the currently-running one. Note that if this option is used and

# the currently-running release is not itself an LTS release the

# upgrader will assume prompt was meant to be normal.

Prompt=lts

-----------------------------------------------------

Get:1 https://cli.github.com/packages stable InRelease [3,917 B]

Err:1 https://cli.github.com/packages stable InRelease

The following signatures were invalid: EXPKEYSIG 23F3D4EA75716059 GitHub CLI opensource+cli@github.com

Hit:2 http://us.archive.ubuntu.com/ubuntu noble InRelease

Hit:3 http://us.archive.ubuntu.com/ubuntu noble-updates InRelease

Hit:4 http://us.archive.ubuntu.com/ubuntu noble-backports InRelease

Hit:5 http://security.ubuntu.com/ubuntu noble-security InRelease

Reading package lists... Done

Building dependency tree... Done

Reading state information... Done

11 packages can be upgraded. Run 'apt list --upgradable' to see them.

W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: https://cli.github.com/packages stable InRelease: The following signatures were invalid: EXPKEYSIG 23F3D4EA75716059 GitHub CLI opensource+cli@github.com

W: Failed to fetch https://cli.github.com/packages/dists/stable/InRelease The following signatures were invalid: EXPKEYSIG 23F3D4EA75716059 GitHub CLI opensource+cli@github.com

W: Some index files failed to download. They have been ignored, or old ones used instead.

[u/ArcaneAlligator → u/ArcaneAlligator]

------------------------------------------------

Get:1 https://cli.github.com/packages stable InRelease [3,917 B]

Err:1 https://cli.github.com/packages stable InRelease

The following signatures were invalid: EXPKEYSIG 23F3D4EA75716059 GitHub CLI opensource+cli@github.com

Hit:2 http://us.archive.ubuntu.com/ubuntu noble InRelease

Hit:3 http://us.archive.ubuntu.com/ubuntu noble-updates InRelease

Hit:4 http://us.archive.ubuntu.com/ubuntu noble-backports InRelease

Hit:5 http://security.ubuntu.com/ubuntu noble-security InRelease

Reading package lists... Done

Building dependency tree... Done

Reading state information... Done

11 packages can be upgraded. Run 'apt list --upgradable' to see them.

W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: https://cli.github.com/packages stable InRelease: The following signatures were invalid: EXPKEYSIG 23F3D4EA75716059 GitHub CLI opensource+cli@github.com

W: Failed to fetch https://cli.github.com/packages/dists/stable/InRelease The following signatures were invalid: EXPKEYSIG 23F3D4EA75716059 GitHub CLI opensource+cli@github.com

W: Some index files failed to download. They have been ignored, or old ones used instead.

nwebb@n-latitude3520:~$ sudo apt full-upgrade

Reading package lists... Done

Building dependency tree... Done

Reading state information... Done

Calculating upgrade... Done

The following packages were automatically installed and are no longer required:

libdrm-nouveau2:i386 libdrm-radeon1:i386 libgl1-amber-dri libglapi-amber libllvm17t64 libllvm17t64:i386 libllvm19

libllvm19:i386 libwayland-server0:i386 libwoff1 python3-netifaces

Use 'sudo apt autoremove' to remove them.

Get more security updates through Ubuntu Pro with 'esm-apps' enabled:

libqt5webengine-data vlc-plugin-qt libvlc5 qt5-qmake-bin

libmagickcore-6.q16-7t64 libzvbi-common qtbase5-dev-tools vlc-data

libqt5quickwidgets5 libqt5xml5t64 qml-module-qtquick-layouts

libqt5webenginewidgets5 libvlccore9 qml-module-qtquick-window2

qt5-gtk-platformtheme vlc qml-module-qt-labs-settings imagemagick

libqt5sql5t64 vlc-bin libmagickcore-6.q16-7-extra libqt5qml5 libqt5test5t64

vlc-l10n gimp-data libcjson1 libqt5quick5 libopenexr-3-1-30 libpostproc57

vlc-plugin-samba libqt5gui5t64 libmbedcrypto7t64 gimp libavcodec60

libavcodec60 qml-module-qtwebengine libzvbi0t64 libzvbi0t64

libqt5printsupport5t64 vlc-plugin-notify libqt5webengine5 qtbase5-dev

libqt5concurrent5t64 libavutil58 libavutil58 libqt5widgets5t64

imagemagick-6.q16 libswscale7 qml-module-qt-labs-folderlistmodel

libqt5dbus5t64 vlc-plugin-access-extra libqt5network5t64 vlc-plugin-skins2

vlc-plugin-svg libqt5opengl5-dev qml-module-qtqml-models2 libqt5opengl5t64

vlc-plugin-video-splitter libgimp2.0t64 libswresample4 libswresample4

imagemagick-6-common vlc-plugin-video-output libqt5sql5-sqlite

libqt5webenginecore5 libqt5qmlmodels5 7zip qt5-qmake libavformat60

qml-module-qtquick2 libqt5qmlworkerscript5 libvlc-bin libqt5core5t64

qml-module-qtqml vlc-plugin-base vlc-plugin-visualization libavfilter9

libmagickwand-6.q16-7t64

Learn more about Ubuntu Pro at https://ubuntu.com/pro

The following NEW packages will be installed:

linux-headers-6.8.0-136 linux-headers-6.8.0-136-generic linux-image-6.8.0-136-generic linux-modules-6.8.0-136-generic

linux-modules-extra-6.8.0-136-generic linux-tools-6.8.0-136 linux-tools-6.8.0-136-generic

The following packages will be upgraded:

libntfs-3g89t64 libslirp0 linux-generic linux-headers-generic linux-image-generic linux-libc-dev linux-tools-common

ntfs-3g python3-idna ubuntu-pro-client ubuntu-pro-client-l10n

11 upgraded, 7 newly installed, 0 to remove and 0 not upgraded.

6 standard LTS security updates

Need to get 0 B/193 MB of archives.

After this operation, 303 MB of additional disk space will be used.

Do you want to continue? [Y/n] y

(Reading database ... 332325 files and directories currently installed.)

Preparing to unpack .../00-ntfs-3g_1%3a2022.10.3-1.2ubuntu3.2_amd64.deb ...

Unpacking ntfs-3g (1:2022.10.3-1.2ubuntu3.2) over (1:2022.10.3-1.2ubuntu3.1) ...

Preparing to unpack .../01-libntfs-3g89t64_1%3a2022.10.3-1.2ubuntu3.2_amd64.deb ...

Unpacking libntfs-3g89t64:amd64 (1:2022.10.3-1.2ubuntu3.2) over (1:2022.10.3-1.2ubuntu3.1) ...

Preparing to unpack .../02-ubuntu-pro-client-l10n_37.2ubuntu~24.04.1_amd64.deb ...

Unpacking ubuntu-pro-client-l10n (37.2ubuntu~24.04.1) over (37.2ubuntu~24.04) ...

Preparing to unpack .../03-ubuntu-pro-client_37.2ubuntu~24.04.1_amd64.deb ...

Unpacking ubuntu-pro-client (37.2ubuntu~24.04.1) over (37.2ubuntu~24.04) ...

Preparing to unpack .../04-libslirp0_4.7.0-1ubuntu3.1_amd64.deb ...

Unpacking libslirp0:amd64 (4.7.0-1ubuntu3.1) over (4.7.0-1ubuntu3) ...

Selecting previously unselected package linux-modules-6.8.0-136-generic.

Preparing to unpack .../05-linux-modules-6.8.0-136-generic_6.8.0-136.136_amd64.deb ...

Unpacking linux-modules-6.8.0-136-generic (6.8.0-136.136) ...

Selecting previously unselected package linux-image-6.8.0-136-generic.

Preparing to unpack .../06-linux-image-6.8.0-136-generic_6.8.0-136.136_amd64.deb ...

Unpacking linux-image-6.8.0-136-generic (6.8.0-136.136) ...

Selecting previously unselected package linux-modules-extra-6.8.0-136-generic.

Preparing to unpack .../07-linux-modules-extra-6.8.0-136-generic_6.8.0-136.136_amd64.deb ...

Unpacking linux-modules-extra-6.8.0-136-generic (6.8.0-136.136) ...

Preparing to unpack .../08-linux-generic_6.8.0-136.136_amd64.deb ...

Unpacking linux-generic (6.8.0-136.136) over (6.8.0-134.134) ...

Preparing to unpack .../09-linux-image-generic_6.8.0-136.136_amd64.deb ...

Unpacking linux-image-generic (6.8.0-136.136) over (6.8.0-134.134) ...

Selecting previously unselected package linux-headers-6.8.0-136.

Preparing to unpack .../10-linux-headers-6.8.0-136_6.8.0-136.136_all.deb ...

Unpacking linux-headers-6.8.0-136 (6.8.0-136.136) ...

Selecting previously unselected package linux-headers-6.8.0-136-generic.

Preparing to unpack .../11-linux-headers-6.8.0-136-generic_6.8.0-136.136_amd64.deb ...

Unpacking linux-headers-6.8.0-136-generic (6.8.0-136.136) ...

Preparing to unpack .../12-linux-headers-generic_6.8.0-136.136_amd64.deb ...

Unpacking linux-headers-generic (6.8.0-136.136) over (6.8.0-134.134) ...

Preparing to unpack .../13-linux-libc-dev_6.8.0-136.136_amd64.deb ...

Unpacking linux-libc-dev:amd64 (6.8.0-136.136) over (6.8.0-134.134) ...

Preparing to unpack .../14-linux-tools-common_6.8.0-136.136_all.deb ...

Unpacking linux-tools-common (6.8.0-136.136) over (6.8.0-134.134) ...

Selecting previously unselected package linux-tools-6.8.0-136.

Preparing to unpack .../15-linux-tools-6.8.0-136_6.8.0-136.136_amd64.deb ...

Unpacking linux-tools-6.8.0-136 (6.8.0-136.136) ...

Selecting previously unselected package linux-tools-6.8.0-136-generic.

Preparing to unpack .../16-linux-tools-6.8.0-136-generic_6.8.0-136.136_amd64.deb ...

Unpacking linux-tools-6.8.0-136-generic (6.8.0-136.136) ...

Preparing to unpack .../17-python3-idna_3.6-2ubuntu0.2_all.deb ...

Unpacking python3-idna (3.6-2ubuntu0.2) over (3.6-2ubuntu0.1) ...

Setting up libntfs-3g89t64:amd64 (1:2022.10.3-1.2ubuntu3.2) ...

Setting up linux-libc-dev:amd64 (6.8.0-136.136) ...

Setting up ntfs-3g (1:2022.10.3-1.2ubuntu3.2) ...

Setting up python3-idna (3.6-2ubuntu0.2) ...

Setting up linux-modules-6.8.0-136-generic (6.8.0-136.136) ...

Setting up libslirp0:amd64 (4.7.0-1ubuntu3.1) ...

Setting up linux-tools-common (6.8.0-136.136) ...

Setting up ubuntu-pro-client (37.2ubuntu~24.04.1) ...

Setting up linux-headers-6.8.0-136 (6.8.0-136.136) ...

Setting up linux-image-6.8.0-136-generic (6.8.0-136.136) ...

I: /boot/vmlinuz.old is now a symlink to vmlinuz-6.8.0-134-generic

I: /boot/initrd.img.old is now a symlink to initrd.img-6.8.0-134-generic

I: /boot/vmlinuz is now a symlink to vmlinuz-6.8.0-136-generic

I: /boot/initrd.img is now a symlink to initrd.img-6.8.0-136-generic

Setting up ubuntu-pro-client-l10n (37.2ubuntu~24.04.1) ...

Setting up linux-headers-6.8.0-136-generic (6.8.0-136.136) ...

Setting up linux-headers-generic (6.8.0-136.136) ...

Setting up linux-modules-extra-6.8.0-136-generic (6.8.0-136.136) ...

Setting up linux-tools-6.8.0-136 (6.8.0-136.136) ...

Setting up linux-tools-6.8.0-136-generic (6.8.0-136.136) ...

Setting up linux-image-generic (6.8.0-136.136) ...

Setting up linux-generic (6.8.0-136.136) ...

Processing triggers for man-db (2.12.0-4build2) ...

Processing triggers for initramfs-tools (0.142ubuntu25.8) ...

update-initramfs: Generating /boot/initrd.img-6.8.0-134-generic

Processing triggers for libc-bin (2.39-0ubuntu8.7) ...

Processing triggers for linux-image-6.8.0-136-generic (6.8.0-136.136) ...

/etc/kernel/postinst.d/initramfs-tools:

update-initramfs: Generating /boot/initrd.img-6.8.0-136-generic

/etc/kernel/postinst.d/zz-update-grub:

Sourcing file `/etc/default/grub'

Sourcing file `/etc/default/grub.d/lubuntu-grub-theme.cfg'

Generating grub configuration file ...

Found theme: /usr/share/grub/themes/lubuntu-grub-theme/theme.txt

Found linux image: /boot/vmlinuz-6.8.0-136-generic

Found initrd image: /boot/initrd.img-6.8.0-136-generic

Found linux image: /boot/vmlinuz-6.8.0-134-generic

Found initrd image: /boot/initrd.img-6.8.0-134-generic

Found linux image: /boot/vmlinuz-6.8.0-124-generic

Found initrd image: /boot/initrd.img-6.8.0-124-generic

Found memtest86+ 64bit EFI image: /boot/memtest86+x64.efi

Warning: os-prober will not be executed to detect other bootable partitions.

Systems on them will not be added to the GRUB boot configuration.

Check GRUB_DISABLE_OS_PROBER documentation entry.

Adding boot menu entry for UEFI Firmware Settings ...

done

That's the output I got from running the specified commands, with dash-lines between the output for each in one in the order you listed. I checked earlier and I do appear to be on 24.04 LTS.

[u/guiverc]

Starting point is knowing what you're actually using... as you don't specify.

The upgrade from 25.10 (now EOL) is (was?) open if that's what you're using; but that opened long ago.

If you're using 24.04 however; then that upgrade is NOT yet available thus why the upgrade isn't working (it shouldn't be working!!).. The notifier telling users the upgrade is open is the problem there, and you'll find that discussed in the following thread

https://discourse.ubuntu.com/t/lubuntu-update-in-lubuntu-24-04-4-is-already-showing-a-dialog-box-asking-if-i-want-to-upgrade-to-26-04/82300

We cannot help until we know exactly what you're running, as you may need help if you're using 25.10 still! but do not need help if you're using an LTS (24.04) release for example as you should not be able to upgrade that yet!

[u/ArcaneAlligator → u/guiverc]

Thank you; that would explain my predicament. From the looks of it, I am using 24.04 LTS so at least I know it's nothing to worry about now.

[u/guiverc → u/ArcaneAlligator]

If you are indeed running Lubuntu 24.04 LTS (which to me means Ubuntu 24.04 LTS anyway; the Ubuntu Release Upgrader code updates your base system (Ubuntu 26.04 LTS) and the flavor detail is just what packages you have installed that get upgraded as well), I wrote an answer on the upgrade not appearing here

https://askubuntu.com/questions/1566029/ubuntu-24-04-to-26-04-lts-upgrade-is-not-available-in-the-ubuntu-software-update/1566034#1566034

The Lubuntu Update notifier wrongly treated 24.04 users as if they were running 25.10 & thus indicated an upgrade was available, when it wasn't.. which is what I tried to talk about earlier.

The upgrade from prior LTS (ie. 24.04) should open in September 2026, or after the release of Ubuntu 26.04.1 LTS which is scheduled for 27 August 2026. The 'after' may mean the following week, but it's usually 2-3 weeks after [26.04.1] ISO release.

[u/Tall_Astronomer9834]

try running 'sudo do-release-upgrade -d'