10 Reasons Why Migrating from Qt5 to Qt6 Is Worth It

If you develop desktop applications with Qt, you might wonder whether it’s the right time to upgrade from Qt5 to Qt6. As support for Qt5 gradually winds down and the software landscape evolves, the benefits of migration become increasingly compelling. In this article, we’ll break down the top 10 reasons why moving to Qt6 is a smart investment for your projects and your team. We’ll also provide practical examples, troubleshooting tips, and best practices to guide a smooth transition.

Whether you build cross-platform business tools, creative software, or embedded solutions, making the leap to Qt6 can unlock new levels of performance, modernization, and future-proofing. Let’s explore the advantages, common challenges, and actionable steps for a successful migration.

1. Enhanced Performance and Efficiency

Qt6 Delivers Faster Apps

The performance improvements in Qt6 are significant. With a modernized rendering pipeline and refined core libraries, Qt6 applications load faster, run smoother, and handle heavy workloads more efficiently. Benchmarks show up to 25% faster rendering for graphics-intensive apps compared to Qt5.

Examples of Performance Gains

• High-frequency trading platforms see reduced latency.
• 3D modeling tools benefit from accelerated rendering.
• Large enterprise dashboards load complex graphs more quickly.

Takeaway: Upgrading to Qt6 can drastically improve your application's responsiveness, especially for graphics-heavy or data-driven use cases.

2. Modern Graphics and Rendering Capabilities

Advanced Rendering with Qt Quick 3D

Qt6 introduces Qt Quick 3D as a first-class citizen, making it easier to implement 3D graphics and stunning visual effects. The new rendering architecture is built on top of Vulkan, Metal, and Direct3D, ensuring your apps leverage the latest GPU features on every platform.

Real-World Example

• Medical imaging software now offers real-time volumetric rendering.
• CAD tools can utilize advanced shading and reflections.

"Moving to Qt6 let us deliver visualizations our users had only dreamed of in Qt5."

3. Improved Cross-Platform Support and Future-Proofing

Stay Compatible with Modern Systems

Modern operating systems like Windows 11 and the latest macOS require up-to-date frameworks. Qt6 provides:

• Better support for ARM architectures (including Apple Silicon)
• Improved integration with Wayland (see Wayland vs X11: Impact on Qt)
• Continued updates and long-term support

Why This Matters

By migrating now, your apps remain future-ready and avoid last-minute compatibility scrambles as Qt5 sunsets.

4. Streamlined APIs and Cleaner Codebase

Simpler, More Consistent APIs

Qt6 refactored many modules for consistency and clarity. Deprecated and redundant APIs from Qt5 were removed or unified, reducing confusion for developers.

Step-by-Step Example

// Qt5
QString str = QStringLiteral("Hello");
str = str.trimmed();

// Qt6 (more consistent API usage)
QString str = QStringLiteral("Hello").trimmed();

This cleaner API design makes new code easier to write, maintain, and review.

Best Practice:

• Leverage Qt6’s improved documentation to refactor legacy code during migration.

5. Superior Internationalization and Accessibility

Building for Global Audiences

Qt6 enhances localization support with better handling for right-to-left languages, Unicode, and pluralization rules. Accessibility APIs are also improved, making your apps more inclusive.

Common Pitfall to Avoid

• Overlooking locale-specific formats when migrating layout code.

Tip: Test your UI using different system locales to catch issues early.

6. Optimized for Embedded and Mobile Devices

Lightweight and Modular Architecture

Qt6 was designed with modularity in mind. You can include only what you need, resulting in smaller binaries and faster startup on resource-constrained devices.

Real-World Scenario

• Industrial controllers now deploy with up to 30% smaller binaries.
• Automotive dashboards run smoother on ARM hardware.

"Qt6 let us cut our deployment image in half without losing functionality."

7. Better Integration with Modern Toolchains

Support for Latest C++ Standards

Qt6 fully supports C++17 and beyond, enabling you to use the latest language features and libraries. Integration with modern build systems like CMake is now the default, streamlining project setup and builds.

Example: Migrating Your Build System

# Qt5 (qmake)
QT += core gui

# Qt6 (CMake)
find_package(Qt6 COMPONENTS Core Gui REQUIRED)
target_link_libraries(MyApp PRIVATE Qt6::Core Qt6::Gui)

This makes it easier to onboard new developers and maintain large codebases.

8. Stronger Community and Ecosystem Support

Access to New Features and Long-Term Support

Qt6 is now the main focus of the Qt Company and the open source community. New libraries, bug fixes, and security patches are prioritized for Qt6, ensuring your app stays secure and competitive.

Community Resources

• Active forums and Discord channels for troubleshooting
• More frequent updates, tutorials, and example projects

Staying on Qt5 means missing out on critical improvements and security patches.

9. Simplified Migration Path and Tooling

Migration Tools and Guides

The Qt Company provides detailed migration guides and tools to help you upgrade from Qt5 to Qt6. Automated scripts can identify deprecated APIs and suggest replacements.

Step-by-Step Migration Process

1. Audit your project for deprecated Qt5 APIs.
2. Update your build system to CMake (if needed).
3. Refactor code for new module structure.
4. Test thoroughly on all target platforms.

Most teams report migration times of a few days to a few weeks, depending on project size.

10. Competitive Advantage and Future-Proofing

Stay Ahead of the Curve

Adopting Qt6 gives your desktop applications a competitive edge with modern features, better UX, and ongoing support. Clients increasingly demand cross-platform compatibility and cutting-edge visuals—Qt6 delivers both.

Comparisons with Other Frameworks

• Qt6 matches or exceeds JavaFX and .NET MAUI in performance and flexibility.
• Qt6 is more future-ready for cloud migration of desktop apps.
• Qt6 is better suited for modern Linux desktops using Wayland.

Key Insight: "Migrating to Qt6 means you’re building for tomorrow, not just today."

Common Mistakes and How to Avoid Them During Qt Migration

1. Not Auditing Third-Party Dependencies

Some libraries may not yet support Qt6. Before upgrading, make sure all dependencies are compatible or have viable alternatives.

2. Skipping Thorough Testing

Migration can introduce subtle bugs, especially with new rendering engines or layout systems. Always test on every target OS and hardware configuration.

3. Overlooking Documentation Updates

Qt6’s improved APIs mean your internal documentation and onboarding materials may also require updates for accuracy and clarity.

Best Practices for a Smooth Qt5 to Qt6 Migration

1. Plan Incrementally

Consider migrating component-by-component rather than all at once, especially for large codebases. This reduces risk and helps isolate issues.

2. Leverage Automated Tools

Use the official Qt migration tools to scan for deprecated APIs and syntax differences.

3. Engage the Community

Participate in forums or open source initiatives to get tips, bug reports, and migration success stories from other developers.

Frequently Asked Questions About Qt6 Migration

Is Qt5 still supported?

Qt5 is in long-term support for select licensees, but mainstream updates and new features are focused on Qt6. It’s recommended to migrate to avoid security risks and loss of support.

How complex is the migration process?

For most projects, migration is straightforward. Complexity increases with heavy customizations or reliance on deprecated modules, but detailed guides and tools are available.

What if my users are on older hardware?

Qt6 is optimized for modern systems but still supports a wide range of hardware. Test performance on your user base’s typical devices to ensure compatibility.

Conclusion: Why Migrating to Qt6 Is a Smart Investment

Migrating from Qt5 to Qt6 is more than a technical upgrade—it’s a strategic move that unlocks better performance, modern graphics, and future-proof compatibility. By embracing Qt6, you position your desktop applications for long-term success, user satisfaction, and easier maintenance. Don’t wait for Qt5’s sunset—start planning your migration today.

• Take advantage of enhanced speed and visuals.
• Stay up-to-date with security and community support.
• Build apps that stand out in a competitive market.

Ready to take the next step? Explore more about building high-performance desktop apps or read our guide on migrating legacy applications to the cloud for your modernization journey.