Qt 6.12 is now available as the latest Long-Term Support release of the cross-platform application framework, offering five years of maintenance and improvements to QML development, 2D rendering, Qt Graphs, networking, and platform support.
One headline addition is built-in Hot Reload support in the QML Engine. Developers can see changes to a running QML interface as they edit the code without restarting the application. The feature is available through Qt Creator and the command line using the qmlpreview tool.
Qt CanvasPainter reaches an important milestone in this release. Introduced as a Technology Preview in Qt 6.11, its core API is now production-ready for both C++ and QML. It provides an imperative drawing API accelerated through Qt’s Rendering Hardware Interface.
Alongside it comes the new Canvas2D QML element, modeled after the HTML Canvas API and intended as a modern replacement for Qt Quick Canvas. It lets developers draw shapes using JavaScript while CanvasPainter handles GPU rendering. Canvas2D remains in Technology Preview.
Qt Graphs adds logarithmic axes for 2D graphs, more axis-label customization, and built-in zoom and pan interactions. A new CanvasPainter-based rendering backend is available for workloads with large amounts of frequently changing data.
Another addition is StyleKit, currently available through Qt Labs. It aims to make it easier to maintain a consistent visual style across applications mixing Qt Widgets and Qt Quick, with support for themes like light, dark, and high contrast.
Moreover, QRangeModel gains built-in sorting, faster search, more drag-and-drop control, and additional customization options. QtGrpc adds client-side message compression and limits for incoming message sizes.
Platform support expands with HarmonyOS, now officially supported as an LTS platform in Qt 6.12. Other changes include a new QtQuick.Controls.Native style, additional Qt Quick 3D Physics joint types, improved audio and video support for WebAssembly, and smaller compiled resources through resource deduplication.
As an LTS release, Qt 6.12 will receive maintenance for five years. Qt says the commercial edition has been prepared to meet its part of the EU Cyber Resilience Act requirements, although applications built with Qt still need their own compliance work.
For more details, see the official announcement.