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One free scan finds every outdated or missing driver and matches the right update for your exact hardware.Free scan · exact hardware matchTo migrate an existing Qt 6 application to Qt 6.12 LTS, first compare the 6.12 change notes with the Qt modules and APIs your project actually uses. Then install a Qt 6.12 kit that matches your compiler and deployment targets, reconfigure and build cleanly, and test the application on its supported platforms. This is a Qt 6 minor-version upgrade—not a repeat of the Qt 5-to-Qt 6 port.
What changes when you move to Qt 6.12?
Qt announced Qt 6.12 LTS on September 30, 2026. The company describes it as receiving maintenance over a five-year period; that is Qt’s stated LTS maintenance horizon, not an independent assessment of support outcomes. See the Qt 6.12 release announcement and the release statement by Volker Hilsheimer.
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The practical migration work depends on your project: which Qt modules it links, which APIs it calls, and which compiler, operating systems, and architectures it ships on. Start with those facts rather than assuming every change associated with Qt 6 applies to this upgrade.
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1. Inventory the project you have
Before installing a new kit, record the existing build and deployment setup. This gives you a baseline for checking compatibility and diagnosing regressions.
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- Current Qt 6 version and every Qt module used.
- Compiler, version, and target architecture for each build.
- Build system: CMake or qmake, including project files, toolchain files, and CI configuration.
- Generated code, custom plugins, and any third-party libraries tied to Qt or a specific compiler.
- Every shipped operating system and architecture, plus packaging and deployment steps.
Keep this inventory specific to the application. A desktop build and an embedded or mobile build may have different support constraints even when they share source code.
2. Check the Qt 6.12 changes that intersect your code
Read the Qt 6.12 change notes module by module. Focus on changed or deprecated APIs, behavior changes, and entries for your target platforms. A listed change matters to your upgrade only if it intersects the modules, APIs, or configurations your project uses.
Example: multimedia metadata
Qt 6.12 marks QMediaMetaData::ThumbnailImage as deprecated, and backends will no longer populate it. If your application relies on that metadata key, review the affected code and use CoverArtImage instead where appropriate. Check the change notes for the module and backend relevant to your application.
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3. Confirm that Qt 6.12 supports each target
For every shipped configuration, compare its operating system, CPU architecture, compiler, and required Qt modules with Qt’s supported platforms. Qt says configurations absent from that list are not officially supported, and the configurations may change in later Qt 6.12 patch releases. Do not infer that an older compiler or OS remains supported merely because an earlier Qt 6 version supported it.
Windows 10 requires a forward plan
Qt lists Windows 10 version 1809 or later as supported for Qt 6.12 and identifies Qt 6.12 as the last Qt version to support Windows 10. If Windows 10 is a product target, treat the next Qt upgrade and the product’s OS support strategy as a separate planning decision.
4. Switch to a matching Qt 6.12 kit and reconfigure
Install a Qt 6.12 kit that matches the compiler and toolchain for each target. Then configure from a clean build directory so cached paths or generated files from the previous Qt installation do not obscure configuration problems.
For CMake projects
Qt’s CMake getting-started guide shows the standard pattern: locate the Qt 6 components the project needs and link the corresponding imported targets. For example:
find_package(Qt6 REQUIRED COMPONENTS Core)
target_link_libraries(my_app PRIVATE Qt6::Core)Use the components your application actually uses; this example is not a complete project file. The guide also describes qt_standard_project_setup() for standard defaults, including automatic MOC setup, and qt_add_executable() for defining an executable target. Review your existing CMake structure against the guide and the Qt 6.12 kit rather than replacing build files mechanically.
Qt 6 requires a compiler that supports C++17 or later. That language minimum does not establish that every C++17-capable compiler is supported for every platform: check the platform table for the exact target, compiler, and Qt modules you need.
For qmake projects
If your project uses qmake, select a compatible Qt 6.12 kit and use its qmake and toolchain to configure and build. Check the supported-platform information for your target, and do not translate the project to CMake solely because you are changing Qt minor versions.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.5. Build, resolve relevant diagnostics, and test the deployed app
Build each target configuration and use compiler and linker diagnostics to identify issues. Relate those issues to the modules and APIs in your inventory and the Qt 6.12 notes; do not treat removals from the Qt 5-to-Qt 6 transition as new Qt 6.12 breaks.
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1Fix the driver behind crashes, sound loss and screen glitches2Repair Windows errors before they cause bigger problems3Scan for outdated or missing drivers - takes under a minuteRun the project’s existing checks on its actual deployment matrix: unit and integration tests, UI checks, packaging, and deployment. Include graphics and Qt Quick behavior on the real target devices or operating systems when relevant. The older Qt 5-to-Qt 6 guide notes graphical regressions associated with that major transition; for a project already on Qt 6, that is a reason to validate graphics, not evidence that the same transition change happens again in 6.12.
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Keep Qt 5 porting advice in its proper scope
Qt’s Porting to Qt 6 guide addresses the move from Qt 5. Its advice includes updating an older Qt 5 application, reviewing deprecated or removed APIs and modules, and checking graphics behavior. Those steps may still matter if your codebase retains Qt 5 compatibility code or has not completed that major-version port. They are not a blanket checklist of new work required for an application already running on Qt 6.
For minor-version changes within Qt 6, use the relevant version’s change notes to identify the changes that apply to your code.
6. Decide whether the LTS horizon fits your project
Qt’s five-year maintenance statement can inform upgrade planning, but it does not by itself establish that a particular product configuration is covered by a specific commercial support arrangement. Compare your target-platform coverage, compiler and build-system fit, affected API usage, maintenance needs, and licensing or support requirements. Review the supported-platform information and the applicable license terms for your product before relying on a support commitment.
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