Qt6 Support: Qt5 Deprecation & Gentoo's Transition

As Linux distributions prepare for a future without Qt5, the transition to Qt6 becomes increasingly important. This article dives into the implications of Qt5's deprecation, particularly within Gentoo, Alpine, and Ubuntu, and explores the ongoing efforts to embrace Qt6. We'll also examine the resources available to developers for a smoother porting process.

The Sunset of Qt5: What You Need to Know

Qt5's journey is coming to an end. The writing is on the wall: Qt5 has been declared deprecated in Gentoo, signaling a significant shift in the Linux landscape. But what does this mean for developers and users alike? Let's break it down.

First and foremost, The Qt Company's open-source support for Qt5 officially concluded back in 2020. Since then, public availability of LTS (Long-Term Support) releases has been delayed by a year, and access to stable branch repositories has been restricted. Essentially, new LTS tags for the 5.15 branch repository only appear a year after their commercial release. The final Qt5 release occurred on May 19, 2025, meaning that any updates won't be seen until June 19, 2026. Critically, any bugs discovered since last May will remain unfixed and issues not affecting Qt6 since December 8, 2020, will also go unresolved.

Several major distributions, including Gentoo, Alpine, and Ubuntu, are actively tracking Qt6 porting efforts. For instance, Gentoo is already in full swing with Qt5 revdep cleanups, indicating a serious commitment to transitioning away from the older framework. This move is driven by the need to maintain a modern, secure, and well-supported development environment. As Qt5 fades into the background, the focus is shifting to the capabilities and advantages of Qt6.

This transition, while necessary, does present challenges. Developers need to adapt their codebases, learn new APIs, and ensure compatibility with the new framework. However, the good news is that the porting effort from Qt4 to Qt5 was much larger compared to what we expect moving from Qt5 to Qt6. The Qt Company has provided resources to assist developers in this process, which we will explore further in this article.

Embracing Qt6: A Smoother Transition Than Expected

Fortunately, the transition to Qt6 is anticipated to be smoother than the move from Qt4 to Qt5. This is due to several factors, including improvements in the Qt framework itself and the availability of comprehensive porting guides and tools. The Qt Company has invested significant effort in making the transition as seamless as possible for developers.

One of the key resources available is the official Qt6 porting guide. This guide provides detailed instructions and best practices for migrating code from Qt5 to Qt6. It covers various aspects of the porting process, including API changes, compatibility considerations, and potential pitfalls to avoid. By following the guidelines outlined in this document, developers can minimize the effort required to update their applications.

In addition to the porting guide, The Qt Company has also published several blog posts and articles offering practical advice and hints for developers. These resources provide valuable insights into the nuances of the transition and offer solutions to common problems encountered during the porting process. For example, the Qt5Compat library is specifically designed to ease the transition by providing compatibility layers for certain Qt5 APIs.

Another advantage of Qt6 is its improved modularity and performance. The framework has been redesigned to be more efficient and scalable, allowing developers to build faster and more responsive applications. Qt6 also introduces new features and capabilities that were not available in Qt5, such as enhanced support for modern graphics APIs and improved tooling for cross-platform development. By embracing Qt6, developers can take advantage of these advancements and create cutting-edge applications that push the boundaries of what's possible.

Gentoo, Alpine, and Ubuntu: Leading the Charge

Several Linux distributions are taking proactive steps to facilitate the adoption of Qt6. Gentoo, Alpine, and Ubuntu are among the leaders in this effort, actively tracking Qt6 porting and working to remove dependencies on Qt5. Their commitment to Qt6 is a testament to the importance of this transition and its impact on the Linux ecosystem.

Gentoo is perhaps the most aggressive in its approach, with Qt5 revdep cleanups already in full swing. This means that Gentoo developers are actively identifying and removing packages that depend on Qt5, paving the way for a complete transition to Qt6. This effort requires significant coordination and collaboration within the Gentoo community, as developers work together to ensure that all necessary packages are updated and compatible with Qt6.

Alpine Linux is also closely monitoring the Qt6 porting process. The Alpine community has created a tracking issue to monitor the progress of Qt6 adoption and identify any potential roadblocks. By actively tracking the transition, Alpine developers can ensure that the distribution remains up-to-date with the latest Qt technologies.

Ubuntu is another major distribution that is committed to Qt6. The Ubuntu Archive Team is actively working on Qt5 removal, indicating a clear intention to move towards Qt6 as the primary Qt framework. This transition will likely involve updating numerous packages and libraries within the Ubuntu ecosystem, requiring careful planning and execution.

The collective efforts of Gentoo, Alpine, and Ubuntu demonstrate the importance of Qt6 for the future of Linux development. By working together to facilitate the transition, these distributions are ensuring that developers have access to the latest tools and technologies needed to build modern, high-performance applications.

Resources for a Smooth Transition

To aid developers in the transition from Qt5 to Qt6, a wealth of resources are available. These resources range from official documentation and porting guides to community forums and third-party tools. By leveraging these resources, developers can streamline the porting process and minimize the challenges associated with migrating to a new framework.

The official Qt documentation is an invaluable resource for developers of all levels. The documentation provides detailed information on all aspects of the Qt framework, including API reference, tutorials, and examples. Whether you're a seasoned Qt developer or just getting started, the documentation is an essential tool for understanding the intricacies of the framework.

The Qt6 porting guide, as mentioned earlier, provides step-by-step instructions for migrating code from Qt5 to Qt6. This guide covers a wide range of topics, including API changes, compatibility issues, and best practices for ensuring a smooth transition. By following the recommendations in the porting guide, developers can avoid common pitfalls and minimize the effort required to update their applications.

In addition to the official resources, numerous community forums and online groups offer support and guidance for developers migrating to Qt6. These forums are a great place to ask questions, share experiences, and learn from other developers who have already made the transition. By participating in the community, developers can tap into a wealth of knowledge and expertise that can help them overcome challenges and accelerate their learning.

Third-party tools are also available to assist with the porting process. These tools can automate certain tasks, such as identifying API changes and generating compatibility code. While not all tools are created equal, some can significantly reduce the manual effort required to port an application from Qt5 to Qt6.

Conclusion

The transition to Qt6 is a necessary step for the Linux ecosystem, driven by the deprecation of Qt5 and the need for a modern, well-supported framework. While the transition may present challenges, the availability of comprehensive porting guides, active community support, and the proactive efforts of distributions like Gentoo, Alpine, and Ubuntu make the process manageable. By embracing Qt6, developers can take advantage of its improved performance, modularity, and new features to build cutting-edge applications that push the boundaries of what's possible. The future is Qt6, and the time to transition is now.

For more information on Qt6 and the porting process, visit the Qt Company's official website. This resource provides in-depth documentation, tutorials, and community support to help you navigate the transition smoothly.