By Windows 10 widgets, do you mean UWP/Metro/Fluent widgets? In my opinion, the screenshot you linked is still common in Windows 10 apps.

If you want something closer to Metro, you can use Qt Quick and https://doc.qt.io/qt-5/qtquickcontrols2-styles.html#universa.... But Qt Widgets does not ship with a Metro-like theme.

Newer Windows 10 apps have Fluent design, including acrylic effects. I don't know if Qt Quick 2 supports that, but I'm not optimistic they've updated the appearance to match.

Yes I'm thinking about fluent design widgets/theme.

I don’t know why 3rd-party widgets would bother with fluent design when the 1st-party offerings (e.g. WPF) don’t. Not even new Edge uses fluent design controls.

WinUI sort of has fluent, but it is extremely inconsistent. When should things be rounded vs squared? It’s completely inconsistent internally.

Even if Qt wanted to go fluent they’d have a hard time finding any concrete examples to work off of. I can’t think of any “fluent” apps that are consistent with themselves, consistent with the design system, and not breaking major rules.

FWIW Microsoft has broken, twisted and sheared off the look and feel of Windows so severely in the releases since Windows 7 that it's less visually (and interactional-y) consistent than a Linux desktop in 2013 running a mix of Qt 4/5 and Gtk 2/3 apps, which truly is an achievement. Whatever era of Windows widget styling you're using, no one can argue it looks wrong, since nothing looks right any more. Half of the dialogs in Windows nowadays look like they were made by a confused 12 year old who just discovered BS_FLAT and uses it on everything.

The big difference between OS X/macOS and Windows is that when Apple restyle the UI, they make sure even the oldest apps get the new styles, though maybe not a full makeover. Microsoft on the other hand don't seem to want to do this? Even if they can't update third-party apps, why do they give so little attention to the built-in stuff? There's still the odd dialog straight out of Windows 3.1 in there even.

> I don’t know why 3rd-party widgets would bother with fluent design when the 1st-party offerings (e.g. WPF) don’t.

Sounds like an opportunity.

To do what? Use the fluent design widgets? Why would anyone want that?

If I'm asked at work to develop a multiplatform desktop application tomorrow, I will skip Qt because it looks too old fashioned on windows compared to what is developed nowadays.

I mean, Qt doesn’t have any native widgets for any OS (to the best of my knowledge and unless things have changed). They just have “skins” for their own widgets that mimic (sometimes successfully) the underlying platform’s native widgets. So all you’re really asking for is a new theme, unless you really meant “native” in which case the answer is no.

They started using native widgets a long while ago, but they can still be skinned.

Qt Widgets does not use native widgets on Win32 (I heard they're called "windows" there). It only spawns a single native window, and performs all input handling itself. Qt 5 has a mode (https://doc.qt.io/qt-5/qwidget.html#native-widgets-vs-alien-...) which uses native Win32 widgets, but they're more like blank canvases drawn by Qt, than actual Win32 push buttons, and still look slightly off. And it reduces performance.

Native widgets cannot be "skinned" on Windows and macOS, at least not to any appreciable extent.

They definitely can on Windows, and this is how many skinned programs were developed in the past. It's called owner draw.