Baseline

This page is the validated Ubuntu 26.04 LTS + GNOME reference baseline. It is one target in a larger matrix, not the whole guide. The other targets and their roles are documented in Platform Targets.

The values are stored in src/data/baseline.json. The page imports that file, and the local documentation MCP server (docs) reads the same data.

Validated baseline

Area	Validated value
Ubuntu	26.04 LTS (Resolute Raccoon)
Display session	Wayland
GNOME	50
GTK	4.22
libadwaita	1.9
Qt	6.10.2
KDE Frameworks	6.24
KDE Plasma	6.6
GNOME Flatpak runtime	`org.gnome.Platform//50`
KDE Flatpak runtime	`org.kde.Platform//6.10`
Snap base	`core26`
Flatpak	1.16.6
snapd	2.78
Python	3.14
GCC	15.2
LLVM/Clang	21
Rust	1.93.1
Go	1.26
.NET	10
Java	25
Zig	0.15.2
Astro	7.4.8
Starlight	0.42.10
Node.js	24

Ubuntu support window

Support	Ends
Standard support	May 2031
Ubuntu Pro	May 2036
Legacy add-on	May 2041

Ubuntu Pro is optional for app development. The baseline records the support window so readers can judge whether a release is a reasonable target; it does not make Pro a requirement.

Baseline is not minimum support

The baseline is the tested reference environment. It is not a claim that older releases are unsupported, and it is not a promise that every combination of components works together.

Use the baseline when you need the current, validated target for examples, screenshots, and recommendations.
Define a separate minimum-version policy when you ship a library or a package for an older LTS.
Use compile-time version checks (GTK_CHECK_VERSION, QT_VERSION_CHECK) or Rust feature flags, and guard newer APIs only when you genuinely support older releases.
A component can be newer than the baseline in a Flatpak runtime; record that difference in the manifest, not by rewriting this page.

Review

Validated on: November 10, 2026
Next review due: May 10, 2027

The review date is a trigger, not a guarantee. When it passes, open an issue for the review, re-check the primary sources below, update src/data/baseline.json, and run the verification steps. The review is manual until a scheduled freshness check is in place.

Local validation

On Ubuntu 26.04.1, the following were checked directly while preparing this baseline:

gnome-shell --version → GNOME Shell 50.1
apt-cache policy libgtk-4-1 libadwaita-1-0 → GTK 4.22.4, libadwaita 1.9.1
apt-cache policy qt6-base-dev → Qt 6.10.2
apt-cache policy dotnet10 openjdk-25-jdk zig → dotnet10, openjdk-25-jdk, and zig are available
snap info core26 → core26 is available in the Snap Store
flatpak --version → Flatpak 1.16.6
snap --version → snapd 2.78
desktop-file-validate and appstreamcli validate --no-net on the first-app examples → pass

These checks supplement the upstream sources; they do not replace them. Re-run the commands when the baseline is reviewed.

Primary sources

Updating the baseline

Update src/data/baseline.json.
Move validated_on to the review date and set review_due six months later.
Run npm run check:baseline.
Run npm run build and check the pages that link here.
Update the primary-source links if a source moved.
Commit the change and note the upstream release in the commit message.

The update is a normal OpenSpec change. It should explain which upstream release triggered it and which pages were re-checked.