Qt Software U-turns, offers an LGPL licence option for Qt 4.5
Nokia have announced that Qt 4.5, the next version of the Qt GUI tool kit due in March, will also be available under an LGPL licence. The change in Qt Software's position is quite major given that previously an FAQ reply on their site to the question "Why isn't Qt released under the LGPL" described the LGPL as "only a half-hearted Open Source Software license" and claimed "If we had used it we could no longer sell commercial licenses for Qt". Qt Software and Nokia seem to have changed their mind and the same FAQ now reads "Following the Nokia acquisition, our goals have changed from being focused on revenue generation to supporting Nokia’s overall software strategy through the vision of 'Qt Everywhere'."
Nokia will be retaining the current licensing options; a commercial licence for developers who wish to use QT in a proprietary manner and the GPL licence which allows developers to use QT in free software only. The LGPL option will allow developers to use QT in proprietary or free software projects, and only requires that their changes to the QT library itself be shared with others. The change only affects Qt 4.5, with the licensing terms on previous versions of Qt being unchanged.
The change was welcomed by Mark Shuttleworth of Canonical and the Ubuntu project who said "Qt is used extensively in Kubuntu and KDE applications, and Canonical is delighted to see this breakthrough in its licensing model". Second Life developer Linden Lab's Joe Miller also welcomed the change saying "We applaud Nokia's move to simplify the licensing of Qt" and adding "the new licensing has greatly simplified our decision to pursue QtWebkit for integration into Second Life."
More details on how the new licensing will work will be available closer to the release date. Qt Software has said that it will be opening up the development process for Qt with more public resources and repositories in the Qt 4.5 release. It also plans to make support services available to all Qt 4.5 users, regardless of the licence they use, with free and paid support options available.
The QT library is at the heart of the KDE desktop, providing a cross platform C++ GUI tool kit which is available on Linux, Mac OS X and Windows. Qt Software also provide a Java binding for QT, and unofficial support for Qt is available for Python, Ada, Perl, Pascal and PHP. A version of the Qt tool kit is also currently in beta for the S60 range of mobile phones and devices.