The KDE desktop gets an overhaul with Plasma 6 [LWN.net] (2024)

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By Joe Brockmeier
February 28, 2024

It's been nearly 10 years sinceKDEPlasma5,which is the last major release of the desktop.On February28 the project announced its "mega release" of KDEPlasma6, KDE Frameworks 6, and KDE Gear24.02 — all based on the Qt6 development framework. Thisrelease focuses heavily on migrating to Wayland, and aspires to be a seamlessupgrade for the user while improving performance, security, and supportfor newer hardware. For developers, a lot of work has gone into removingdeprecated frameworks and decreasing dependencies to make it easier to writeapplications targeting KDE.

What's in Plasma 6

For the purpose of this article, we'll mostly look at Plasma and Frameworks, as Gear24.02contains too many applications like KMail, Kate, and the Kdenlivevideo editor that deserve more attention in their own right. I ran FedoraKinoite's nightlyreleases with pre-release Plasma6 packages, which has proved pleasantlystable and performant on an aging ThinkPadX280 with 16GB of RAM and aCorei7-8650U CPU.

The difference between Plasma5 and 6 is apparent, but notpronounced. Users who are comfortable with Plasma5 are unlikely to feeldiscomfited with Plasma6, or have a hard time adapting to the changessprinkled throughout the desktop. Plasma6 hasa number of changes to default settings. The big change, of course, is Waylandas the default graphical session.

Plasma6 also has a smattering of smaller, less controversial changes. For example, prior toPlasma6, the desktop defaulted to single-click to open a folder, launch aprogram, or open a file. Users coming from other operating systems orLinux desktop environments are often used to double-clicking to do thesethings. Now, KDE upstream has relented on using a single-click to open files anddefaults to double-click instead. Distributions like Fedora, Kubuntu, andManjaro had been changing the upstream default anyway, so KDE developer Nate Graham suggesteddisabling the feature. "Distros are closer to users and clearly the feedback they've beengetting is that double-click is a better default...Let's admit it and switchto double-click by default ourselves".

Plasma6 is also supposed to do away with the default of using the scrollwheel on the desktop to switch virtual desktops. However, this setting isstill active in Fedora Kinoite as of this writing. Scrolling to switch virtualdesktops has been the default for some time, but Graham argued in another proposalto disable the feature because it can easily surprise users with unexpectedand unwanted behavior. Users who prefer the old behavior can toggle itback on in the "Mouse Actions" settings under "Desktop Folder Settings",so it's not going away entirely. Another change to scrolling behaviorin this release is that clicking on a scrollbar moves the window tothelocation clicked, rather than one "page" at a time. This is meant toreduce the amount of fiddling with the scroll wheel to move up or down a long"distance", in order to be a better option for users with repetitive strain injuries(RSIs) — or for users who'd like to avoid RSIs in the first place.

Breeze is Plasma's default theme and it has been updated for Plasma6, but it's a subtle change— sort of like repainting a room and changing the color from "flat white"to "eggshell white". It has some changes to spacing that make it feel alittle less crowded, and it has fewer lines separating UI elements. The SystemSettings application has also been revamped. This may be more noticeable, assome of the settings have migrated to new locations. The nice thing about KDEis that so much is configurable, but finding configuration settings is stilla challenge in Plasma6. For example, the aforementioned setting to scrollvirtual desktops is found in the Desktop Folder Settings application, butnot in the System Settings application under the Virtual Desktop settings.

Dolphin, KDE's file manager,had its configuration settings redesigned to make them easier to navigate. Theprior version of Dolphin included six tabs of settings for navigation, itscontext menu, startup behavior, view modes, behavior of the trash, andgeneral settings. The redesign condenses this into four tabs, scooting thenavigation options and startup options into the new interface tab. It also addsa fifth tab for user feedback, with options to contribute statistics andparticipate in surveys. These are, as one would expect from an open-sourceproject that respects its users, set to share no data by default. Userswho wish to participate, though, can choose just how much participationthey're willing to engage in. This ranges from sharing just a few detailslike version of the application and operating system, to more telemetrylike screen resolution, time Dolphin is used, how many network shares areavailable, and more.

The Dolphin interface changes are minor. Instead of showing recentfiles from today and yesterday, Dolphin now shows recent files and recentlocations. Settings for file history are system-wide, and found in SystemSettings rather than Dolphin's settings — users can opt for keepinghistory "forever" or a period of months, or turn off history entirely. (Days orhours do not appear to be an option.) Users can also specify the applicationsallowed to access file history, rather than granting access to any application.

Plasma6 on Wayland has some support for highdynamic range (HDR) and color management, depending on the applicationand if one has a supported monitor. Sadly, the monitors I have on hand are notsupported. One thing that did work nicely, however, was setting thescaling for a laptop monitor and external monitor, independently. It was easy to set theexternal monitor to 100% scaling while the ThinkPad screen was set to 125% so that windows appearedto be the same size when moved from one monitor to the other.

The Plasma Search feature, which is part of KRunner and theKickoffapplication launcher, has been refactoredand is claimed to be much faster in this release. The release announcementclaimed major speedups for searching local documents and for applications,while reducing CPU usage. It's hard to verify this, but KRunner did feel snappywhen performing web and document searches. Spectacle,KDE's screenshot utility, now takes screenshots and recordings of the entire desktop, an applicationwindow, or just a selection of the screen. This promises to be a handy toolto create tutorials, or share a recording of application behavior when filinga bug.

KDE giveth, and KDE taketh away. As is common with major updates, somefeatures and settings have been removed due to design changes or difficultywith underlying drivers or software. For example, GUI configuration for Synapticstouchpads and evdevinput devices has been removed because the drivers have been superseded with libinputin Wayland. Unmaintained features like the Air theme,iconview for System Settings, and KHotkeyswere all scuttled in this release. The ability to grabwallpapers from the Unsplash free stock image site was removed due to APIchanges and the QuickShareapplet for file transfer was dropped because it never worked asintended.

Under the hood

Even though Plasma6 may not feel like a major update, a lot of work has goneinto KDEFrameworks6 to make it possible. I asked KDE developerCarl Schwan by email about the developer-facing changes and plans for KDE5 nowthat Plasma6 has been released. Schwan said most of the work inFrameworks6 was about reducing rather than adding features. Schwan pointedto removal of deprecated frameworks, like KHtml, the KJS javascript engine,and KHotkeys. The project has also worked to get rid of deprecated Qt APIs,such as QtCodecs, and to decrease dependencies between frameworks so externalQt applications can just use one or two KDE frameworks. Schwan also said thatKDE has removed a lot of APIs "which were barely used or [...] have betteralternatives either in another framework or in Qt itself". In particular,he noted that KDE's plugin system has moved from two APIs to a single API.

Schwan said that Qt6 itself didn't have many API changes, butit did add an abstraction layer for graphics APIs like Metal, Vulkan,OpenGL, and DirectX "instead of only supporting OpenGL+Angle". Inaddition, Qt has switched to CMake, awayfrom the qmakebuild system, which Schwan said helped a lot to improve developertooling. Finally, Qt6 brought a number of improvements to Qt Wayland,which Schwan said had been driven forward in part by KDE developers.

Support for KDE 5 and X11

Plasma6 is likely to be a littlebit rough around the edges for a while, and users might want to review knownissues before deciding to upgrade. ObviouslyPlasma6 won't be immediately available in mostdistributions, but users can refer to KDE's community wiki for instructionson how to test Plasma6 right away. Users can choose to buildfrom source, try the KDE neontesting edition, or try one of the other distribution-specific methods forFedora, Gentoo, KaOS, NixOS, or openSUSE.

There is no rush to switch — KDE5 is not quite out of the picturejust yet. On February12, on the Plasma development list, David Edmundson saidhe'd seen enough patches that should gointo5.27 to warrant another release. Justin Zobel agreedand noted that "many distros won't [adopt] it for sometime. Major bugfixes and security fixes should definitelycontinue being applied until such time that most major distroshave updated to 6". Valorie Zimmerman, from the Kubuntu project, saidthis is good news since the next long-term support (LTS) release for Kubuntu iscoming in March and won't be based on Qt6. On February19, Jonathan Riddell reportedthe Plasma team planned to do a Plasma5.27.11 release on March6.

Even though many in the Fedora project are eager to drop X11 support, KDE upstreamplans to continue including X11 support for users who depend on it in theshort term. Users can expect to see supportin Plasma6 as well, but Schwan says there's "no fixed timeline" withvarious estimates ranging from two to five years before support is fullyremoved. He stressed that there will be "plenty of communicationbeforehand" and the project "certainly won't drop the support fromone day to the other".

Overall, Plasma6 looks to be a smooth upgrade for users, andKDEFrameworks6 seems to be a solid foundation for the next fewyears of KDE development. It should be interesting to watch how Plasma evolves over the next few years.