Removing Qt 5 from Ubuntu before the release of 26.04 LTS

As we did with Qt 4, it is time to consider a firm timeline for removing Qt 5 from the Ubuntu archive. This includes KDE {Applications,Frameworks,Plasma} 5 and every package depending on them.

The porting process this time around is much easier than it was from 4 to 5. You can find official documentation on porting here and here. You can also use the Qt5Compat library, if your application is not quite Qt 6-ready yet, but you would like to utilize Qt 6.

To quote from upstream:

Porting from Qt 5 to Qt 6 has been intentionally kept easy. There has been a conscious effort throughout the development of Qt 6 to maintain as much source compatibility with Qt 5 as possible.

The firm goal is to request for removal of Qt 5 en masse at the start of the Ubuntu 26.04 cycle, so 26.04 is released without it. If an Ubuntu Archive Administrator is willing to take this work on and wants to volunteer ahead of time, please reach out to me directly.

You can find a crude status page for packages in the Ubuntu archive that need to be ported here. This list is not a single source of truth, but should be considered a good starting point if you are looking to help.

Please, send your patches upstream. We do not want to keep Ubuntu deltas simply for Qt 6 porting, unless it is a native package only existing in Ubuntu. We will start filing bugs against all the affected Ubuntu and Debian packages at the start of next cycle.

If you have any questions on timing, porting, or removal, feel free to reach out to me directly, join our Ubuntu Qt Matrix channel for real-time progress updates on porting, transitions, and more, or join the Ubuntu Flavors Matrix channel for more general, high-level conversation about flavors’ implementation of Qt 6.

Thanks!

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Practically speaking, the major blocker here is that KDE Plasma now hard-depends on VLC since phonon-gstreamer was archived and not ported to Qt6+KF6.

VLC itself isn’t getting its port to Qt 6 until VLC 4.0 is released, and there’s no known timeline for that release.

Personally, I’d prefer reviving phonon-gstreamer over other options.

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From the Lomiri/ex-Unity8 side, we’ve just got many of the required bits to run a full desktop into Debian, while not yet having a clear plan for migrating to Qt6. Our Lomiri, Lomiri UI Toolkit, etc rely on some deprecated GraphicsEffects which have to be migrated over to Qt6 ways. Estimating this pessimistically, I would say we might not make the cut for 26.04.

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