As a board member of the KDE Free Qt Foundation, I
will give some quick
answers here while I consider how to communicate these facts to the wider
public. Please feel free to quote my answer, or to link to this email in a
mailing list archive.
1. The KDE Free Qt Foundation aims to protect all developers using the Free
Software called Qt. The contracts are therefore not limited to KDE.
As one of
the largest volunteer-driven Free Software communities, KDE is well placed to
be the stewards of the interests of Free Software developers in general.
2. The LGPL licence of all current Qt releases allows use in both proprietary
and Free Software applications and contains to platform-specific restrictions.
This licence grant cannot be retroactively taken away by Digia. In addition,
the KDE Free Qt Foundation can also relicense Qt under a different open source
licence (such as BSD) for general, even more permissive use. The Foundation
agreed not do so as long as Digia continues to release Qt as LGPL and with
support for at least desktop Linux and Android (“Qt Free Edition”).
3. The contract with Nokia and Digia covers desktop Linux (X11, Wayland can be
easily added in the future
). Digia has signed a second agreement which also
(Necessitas) and is identical to the first agreement in all
other aspects. Both agreements prohibit Digia from releasing a sub-standard
version of Qt as “Qt Free Edition”. In other words: The desktop Linux version
cannot be incomplete compared to the Windows and Mac versions, and the Android
version cannot be incomplete compared to the other mobile platforms.
4. The differences between the various platforms have massively decreased
during the last years. The same codebase is used for the various platforms,
with minimal platform-specific code paths. This makes it more easy for third
parties to provide support for platforms not officially included in Digia’s LGPL
. We have opened discussions on whether to include the Windows and
MacOS platforms (first with Nokia, then with Digia), but we have not reached
any decisions yet given the legals pitfalls caused by the proprietary nature
of these platforms. For example, we do not know whether Microsoft or Apple
will prohibit or punish the development of LGPL-licensed libraries for their
platforms (cf. AppStore rules).
Please feel free to contact me if you have
thoughts on this topic.
The legal framework of the KDE Free Qt Foundation is now more than 15 years
old (see http://kde.org/community/whatiskde/k...foundation.php).
During this time, Trolltech was bought by Nokia, and Nokia sold Qt to Digia.
We had anticipated such contingencies and included very strong legal language
in the agreement and managed to ensure the continued validity of the
protection in all such cases. In addition to protecting Free Software users of
Qt, we have also accompanied various positive evolutions (relicensing to LGPL,
inclusion of the Android platform, and especially the open governance of the
I invite developers using (or potential using) Qt to contact me with comments,
doubts, questions or constructive feedback on our work.