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# Open Source Versions of Qt

Free (or open source) software is software that comes with a license that gives users certain rights. In particular the right to use the software, to modify it, to obtain its source, and to pass it on (under the same terms). Notice that the term "free" is about rights, not money. The Free Software Foundation (creators of the GNU GPL) speaks of free in this context as in "free speech", not as in "no cost".

Qt Software supports the free software concept by providing the Qt Open Source Edition, which is licensed under the GNU General Public License (GPL) (version 3) and the GNU Lesser General Public License (LGPL) (version 2.1). You can use this edition of Qt to create and distribute software with licenses that are compatible to these free software licenses.

The support of open source with the Open Source Versions of Qt has enabled large successful software projects like KDE to thrive, with thousands of developers around the world using open source versions of Qt at no cost to themselves. With the release of Qt 4, open source versions of Qt became available for Unix/X11, Mac OS X, and Windows platforms.

The Open Source Edition can be downloaded from the Qt website.

Please refer to the online License FAQ for answers to frequently asked questions on open source licensing and its implications.

More information on Free and Open Source software is available online:

- GNU GPL: http://www.gnu.org/.
- Open Source licensing: http://www.opensource.org/.

See Licensing Information for a collection of documents about licenses used in Qt.

Information about Qt Commercial License Agreements is available in the Qt Licensing Overview on the Qt website or by email from qt-sales@nokia.com.

If you are in doubt what edition of Qt is right for your project, please contact qt-info@nokia.com.