Proposal to Update Minimum CMake Version to 3.22

[Neal Gompa]

On Sun, Mar 30, 2025 at 8:14 AM Ömer Fadıl USTA <omerusta at gmail.com> wrote:
>
> Dear KDE Core Development Team,
>
> I hope this message finds you well. I would like to propose an update to the minimum required version of CMake for KDE Frameworks and KDE Plasma projects, raising it from 3.16 to 3.22.
>
> The primary reason for this change is that there are currently no distributions that still utilize CMake 3.16. While this transition may be considered late for KDE 6.4, it is essential for KDE 6.5. Our existing Continuous Integration (CI) systems are already using versions of CMake that are newer than 3.16, meaning we do not perform checks for CMake 3.16 compu7yyyatibility.
>
> Furthermore, with the release of Qt 6.9 stable, the minimum required version of CMake for building Qt has been updated to 3.22, as noted in the Qt 6.9 release notes[1]. This change emphasizes the need for us to align our CMake version with the latest requirements to ensure compatibility and maintainability.
>
> It is important to note that while this change primarily affects KDE Frameworks and KDE Plasma, we are not directly responsible for pushing this change across all KDE projects, such as KDE Gears (KDE Apps). Some projects, like Kdenlive and Krita, may be resistant to this change or may prefer a slower transition. However, I believe that updating the minimum CMake version to 3.22 will ultimately benefit our development process and ensure that we are using a more modern and supported build system.
>
> Additionally, with the release of CMake 4.0, support for versions below 3.5 has been officially dropped[2]. This further underscores the importance of keeping our CMake version up to date.
>
> Thank you for considering this proposal. I look forward to your feedback.
>
> [1] : https://doc-snapshots.qt.io/qt6-6.9/whatsnew69.html#build-system-changes
> [2]: https://cmake.org/cmake/help/latest/release/4.0.html#deprecated-and-removed-features
>
> Ps: Sorry for crossposting to kde-core-devel and kde-devel lists.
>

I think it makes sense for us to raise the CMake minimum version ahead
of adopting Qt >= 6.9 as the minimum Qt version. If we decide to do
this in principle, then we'll need to notify the distributions that
we're planning this in preparation of raising the Qt baseline in a
future Plasma release.



-- 
真実はいつも一つ！/ Always, there's only one truth!