Ubuntu 26.04 LTS breaking changes go far deeper than a version bump, cgroup v1 is gone, X11 is history, and Python jumped a full version. Ubuntu 26.04 LTS includes numerous upgrades compared to Ubuntu 24.04. The update from 24.04 to 26.04 LTS has many significant features that should be evaluated by teams running applications on Ubuntu’s Noble Numbat release prior to issuing commands for the update.
Key Insights:
* cgroups V1 are removed in Ubuntu 26.04 LTS; as such all containerized applications and/or virtual machines utilizing them cannot be upgraded.
* Wayland only GNOME 50 is available; there is no fallback to an X11 desktop session for users of legacy applications which require an X11 desktop session.
* Python 3.12 is being replaced by Python 3.13 and the recommended amount of desktop RAM required is increased to at least six (6) gigabytes (GB) versus four (4) GB previously.
* The “sudo” program has been rewritten in Rust to create “sudo-rs”, therefore scripting automations reading the “sudo” program's outputs may require updates.
* Ubuntu 26.04 LTS was released on April 23, 2026.
Ubuntu 26.04 LTS Breaking Changes: The Three With No Fallback
Canonical released Ubuntu version 26.04 LTS on April 23, 2026. The codename for the new version of Ubuntu is Resolute Raccoon. As a result of this codename, it seems clear that Canonical has been willing to "cut" (i.e., remove) legacy items in order to make progress toward modernization. There are three changes made in this version of Ubuntu that do not provide a fallback path; those include removal of cgroup v1, removal of X11 GNOME session, and enforcement of cgroup-based upgrade blockers by the package manager. This means that when an individual or organization attempts to perform an upgrade using one of these items as part of their configuration, they will be unable to complete the upgrade until they have resolved any issues related to the blocker.
It should be noted that Canonical was not arbitrary or capricious in making these decisions. The changes mentioned above were clearly announced over several versions prior to the final release. However, since individuals/organizations who chose to maintain their original installation of Ubuntu 24.04 did so without installing either of the intermediate versions (Ubuntu 25.x), there may be a large amount of time that will pass before they can determine how to implement any of the changes that were included in Ubuntu 26.04 LTS.
🔗 Ubuntu Official Release Notes
Upgrade Blocker:
You can't use cgroup v1 in your applications (containers) or with your application's operating systems if you are using cgroup v1. The release of 26.04 will stop once the upgrade process starts and before proceeding you'll need to convert over to cgroup v2. There isn't a way to enable cgroup v1 again.
The Changes That Actually Hurt: cgroup v2, Wayland, and sudo-rs
Systemd version 259 was included with ubuntu version 26.04, and Systemd removed support from cgroup v1. The cgroup v2 hierarchies now provide the only unified path available. If you're a docker/lxc user who have been able to run container based workloads since the release of version 22.04 for ubuntu, then this migration to cgroup v2 is going to take some time and effort. Even though you've probably already configured your systemd.unified_cgroup_hierarchy=1, if any of your container images are calling out cgroup v1 API's they will either fail silently or loudly depending upon what runtime you are using.
The desktop version of gnome 50 is also wayland only. Support for logging into x11 sessions is no longer provided. However, legacy applications will continue to work via xwayland. Certain applications such as screen capture software, remote desktop clients, and older electron apps may cause problems. Any devops team running a ubuntu gui based environment for gui testing pipeline will want to check their toolchain for any potential issues prior to releasing the update.
Then there is sudo-rs. The classic C-based sudo has been replaced by a Rust version as the default provider. The way output of sudo is formatted changed. If you have scripts that parse sudo verbose output or rely on specific error messages for automation, then that logic will need to be revisited. Also note that password feedback is now enabled by default in sudo, showing asterisks when typing your password. It may seem minor but this breaks an expect script.
Python Pipeline Risk:
Server vs Desktop vs DevOps: Who Gets Hurt Most
| Change | Server / Sysadmin | Desktop User | DevOps / CI-CD |
| cgroup v1 removed | High impact containers may be blocked | No impact | High impact Docker, LXC pipelines at risk |
| X11 GNOME session dropped | No impact (headless) | Medium impact legacy app compatibility | Some impact GUI testing tools may need updates |
| sudo-rs replaces sudo | Low check automation scripts | No impact for normal use | Medium output parsing scripts may break |
| Python 3.12 → 3.13 | Low check installed packages | Minimal impact | High impact CI builds, venvs, pinned deps |
| RAM minimum 4 GB → 6 GB | Servers scale fine | Older machines may not qualify | Check VM provisioning templates |
| initramfs-tools → Dracut | Check custom initrd hooks | Transparent for most users | Bare-metal deploy scripts may need updates |
Ubuntu Desktop Now Needs 6 GB RAM- Here Is the Before and After
RAM Requirement Change:
The minimum of 4 GB of memory to perform a desktop install of Ubuntu 24.04 LTS (the Noble Numbat) and the minimum of 6 GB of memory to have a comfortable desktop experience with Ubuntu 26.04 LTS (the Resolute Raccoon).
The memory requirements for server remain the same as they did when it was first released: 1.5 GB. However, the increase from 4 to 6 GB for Desktops comes from the addition of GNOME 50 and the overhead from composited Wayland. Therefore, desktop installations that are less than 6 GB will be directed to use lighter versions such as Xubuntu or Lubuntu.
How to Upgrade and What to Check First
Direct upgrade paths for 24.04 will be made available at the first official open point release 26.04.1 in late summer of 2026. If a customer wishes to move prior to the first open point release, they can use the dev flag route however Canonical has expressed explicit recommendations to all production teams to wait. For those testing now:
# Step 1: Verify cgroup v2 is active before attempting upgrade
cat /sys/fs/cgroup/cgroup.controllers
# Step 2: Update all packages on 24.04 first
sudo apt update && sudo apt full-upgrade -y
# Step 3: Install the upgrade tool
sudo apt install update-manager-core
# Step 4: Force upgrade (dev flag — not recommended for production)
sudo do-release-upgrade -d
# ⚠️ WARNING: Do NOT run this on production systems before
# verifying cgroup v2 migration and container compatibility./* Fix: pre code block line breaks */
The extended lifecycle support options available as part of the new Ubuntu Pro product offering may be something to revisit if your fleet plans to continue using 24.04 through 2029 while the rest of the world catches up.
What Got Better:
Linux kernel 7.0 has brought in the ability to use both Intel Nova Lake processors (the next generation of Xeon) as well as the newest AMD Zen 6 processors for server applications. It also now enables crash dumps by default. Additionally, with the latest release it introduced an extensible scheduler that will allow greater flexibility in how workloads are distributed across multiple cores.
GNOME 50 comes pre-configured for fractional scaling which was previously not possible without third party software. Also with this version of GNOME you can finally have variable refresh rate support.
PostgreSQL 18, Docker 29, and PHP 8.5 are available from the server side.
As a result of all these enhancements, if your organization is looking at doing a green field deployment (an entirely new installation), then Linux 26.04 would be a great choice.
The broader community’s response to these changes can be seen by looking at our articles that discuss the changes in default networking for Linux 7.0 and the Fedora 44 beta which will give an idea of the direction the broader distros’ are going with their architectures in 2026.
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