As of version 4.5.0, Qt will be released under the LGPL version 2.1. Jaw off the floor yet? Good.
The motivation for the licensing change is summed up by the mantra: "Qt Everywhere". Nokia and Qt Software are committed to removing every single blocking objection against using Qt that it feasibly can. This includes licensing quibbles. Whatever the merit of the GPL vs LGPL arguments were, this is a pragmatic decision taken to make it all a moot point and broaden acceptance of Qt.
As can be seen here, the LGPL v 2.1 is compatible with all the LGPL / GPL version combinations. License exceptions for other Free software licenses will remain in place and commercial offerings for those who need or desire them also remain, complete with commercial support.
Just as exciting is Nthat okia will also be opening up development of Qt to the broader F/OSS
community. The maintainership, governance and overall ownershp of the core products will remain with Qt Software as they have, but a path for external contribution is being built. That includes public repositories and the whole nine yards. Details on this will be provided by Nokia as it becomes available.
This is next step in the evolution of policies around Qt will grow the market for Qt substantially, both in the F/OSS as well as the proprietary software worlds.
Qt everywhere, indeed!
This is not a signal of Qt Software or Nokia distancing itself, slowly or otherwise, from Qt as a viable product and simply "giving it out" to the community as a move towards abandonware. Nokia and Qt have reiterated their commitment to a commercially viable Qt and Qt remains the Nokia mandated toolkit for all their internal development. The simple fact of the matter is that Nokia is not nearly as reliant on the income from Qt licensing as Trolltech was, and this gives them greater latitude to try new approaches to the market.
All-in-all this means tremendous things for Free and Open Source software in general. The possibility of extending the reach of all of our work is exciting in and of itself, and this will undoubtedly lead to a veritable explosion of Qt and KDE adoption.