KDE Plasma's two classic themes, Oxygen and Air, are making a comeback. A group of KDE contributors is actively restoring both ahead of the Plasma 6.7 release, which is scheduled for June 16, 2026.Both themes trace their roots back to the KDE 4 era. Oxygen shipped as the default theme from KDE 4.0, defined by its dark tones and glassy aesthetic. It held that spot until KDE 4.3, when Air took over as the default, bringing a lighter look built around transparency and white as its base color.While Oxygen stuck around into the Plasma 5 and 6 eras, it did so in an increasingly broken condition, and Air eventually got dropped from Plasma entirely.Now, both are getting a second shot thanks to the restoration effort led by KDE contributor Filip Fila, alongside the original Oxygen designer Nuno Pinheiro and several other KDE developers.On the Oxygen side, the panel has been fully reworked and is now orientation-aware, so vertical panels actually behave correctly. A minimized window indicator and a proper switch design were both missing entirely and have now been added.Similarly, adaptive opacity is now supported and enabled by default, and the color scheme bug that was causing readability issues in widgets like System Monitor has been fixed.Air needed its transparency restored to match its original KDE 4 character. That is done now, with blur added behind widgets, improving readability and visual appeal in the process. The panel has also been reworked, a new header and footer design has been added, and Air now has its own switch SVGs.Why now after all this time? Well, KDE's 30th anniversary coincides with the Plasma 6.7 release, and the people behind this want to ship these historically significant themes for the occasion.As of writing, 26 of 40 checklist items have been completed (linked below), with some pending work including gradient banding fixes in Oxygen, missing SVGs for checkmarks, radio buttons, toolbar, and menubar items across both themes, and a timer SVG for Air.And if you want to see what that progress looks like, continue reading! 😬How do these compare to Breeze?From left to right, we have Breeze, Oxygen, and Air.I checked out how Plasma's default Breeze theme compared to Oxygen and Air on a KDE Neon setup, and I must say, things are looking promising. The themes have things like the panel styling, widget backgrounds, and the new switch designs in place.I specifically took a look at the panel and widgets, and these looked very clean, feeling like they belonged in the modern Plasma experience, which is not something you would expect from themes this old.One thing worth noting is that the icons stayed as Breeze regardless of which Plasma Style I picked.As for the difference between these, Breeze is flat by design. Minimal, no frills, gets out of your way kind. Oxygen and Air are not like that, bringing visible depth and some bling to the desktop, but in different ways.While Air leans hard into transparency, making panels and widgets look light and barely there, Oxygen goes the other direction with darker gradients and more visual weight across the board.Personally, I prefer Oxygen as it looks a lot like Windows 7's Aero, which I quite liked back in the day.You can try these out too!First, you have to download the files for Oxygen and Air on a KDE Plasma-equipped system. Next, you have to go into System Settings > Appearance > Colors & Themes > Plasma Style.Here, click on "Install from File..." and select a theme file to install it. Repeat for the other one, then select whichever theme you want and hit "Apply" on the bottom-right.Oxygen ThemeAir ThemeIf you want to stay in sync with the development of these, you can keep an eye out on the GitLab issue tracker and Telegram group for this project.