--- title: "Baseline" description: "The validated Ubuntu 26.04 LTS + GNOME reference baseline: GNOME 50, GTK 4.22, libadwaita 1.9, Qt 6.10, and the packaging toolchain the examples are tested against. The full target matrix is in Platform Targets." url: "https://digitalesich.github.io/linux-desktop-guide/reference/baseline/" section: "Reference" --- # Baseline > The validated Ubuntu 26.04 LTS + GNOME reference baseline: GNOME 50, GTK 4.22, libadwaita 1.9, Qt 6.10, and the packaging toolchain the examples are tested against. The full target matrix is in Platform Targets. 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](/linux-desktop-guide/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 - [Ubuntu 26.04 LTS release notes](https://documentation.ubuntu.com/release-notes/26.04/) - [Ubuntu Desktop documentation](https://documentation.ubuntu.com/desktop/en/latest/) - [Ubuntu for Developers](https://ubuntu.com/developers/docs/) - [GNOME 50 release notes](https://release.gnome.org/50/) - [GTK 4 documentation](https://docs.gtk.org/gtk4/) - [libadwaita documentation](https://gnome.pages.gitlab.gnome.org/libadwaita/doc/main/) - [Qt 6.10 release](https://www.qt.io/blog/qt-6.10-released) - [Qt 6 documentation](https://doc.qt.io/qt-6/) - [KDE Frameworks 6.24](https://kde.org/announcements/frameworks/6/6.24.0/) - [KDE Plasma 6.6](https://kde.org/announcements/plasma/6/6.6.0/) - [Flatpak documentation](https://docs.flatpak.org/) - [Flathub requirements](https://docs.flathub.org/docs/for-app-authors/requirements) - [Snap documentation](https://snapcraft.io/docs/) - [Snapcraft bases](https://ubuntu.com/docs/snapcraft/stable/reference/bases/) - [Snapcraft core24 to core26](https://ubuntu.com/docs/snapcraft/stable/how-to/change-bases/change-from-core24-to-core26/) ## Updating the baseline 1. Update `src/data/baseline.json`. 2. Move `validated_on` to the review date and set `review_due` six months later. 3. Run `npm run check:baseline`. 4. Run `npm run build` and check the pages that link here. 5. Update the primary-source links if a source moved. 6. 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. ## See also - [Platform Targets](/linux-desktop-guide/targets/) - [How Targets Are Chosen](/linux-desktop-guide/targets/selection/) - [Ubuntu Platform](/linux-desktop-guide/platform/ubuntu/) - [Choose Your Stack](/linux-desktop-guide/start/choose-stack/) - [GTK & libadwaita](/linux-desktop-guide/engineering/gtk/) - [Qt & Kirigami](/linux-desktop-guide/engineering/qt/)