LGPLv2.1 is an older version and not recommended by the Free Software Foundation for new projects anymore. LGPLv3 is the current version of the GNU Lesser General Public License.
What is the consequence of not complying with the LGPL/GPL restrictions?
The license agreement has been updated couple of times over the years, mainly because of acquisitions around Qt or updates to licenses and platforms. (the legal non-profit organization behind KDE) in 1998 and it has a license agreement that ensures the availability of Qt under LGPLv3 and GPLv3 licenses for major desktop and mobile platforms.
The Foundation was originally founded by Trolltech and the KDE e.V. The KDE Free Qt Foundation is an organization with the purpose of securing the availability of the Qt toolkit for the development of Free Software and in particular for the development of KDE software. As a result, the KDE Free Qt Foundation was founded and the KDE Free Qt Foundation Agreement created. Compromises with KDE were sought to ensure that Qt would be available for their use under appropriate open source licensing even if Trolltech (the company that founded Qt) would be acquired or go bankrupt.
In the very early days, Qt was already dual-licensed, but the source code was available under proprietary open source licenses. In the early days of Qt, the KDE project and community were the biggest driving force in building the developer ecosystem around Qt. KDE software is based on the Qt framework. KDE is mainly known for its Plasma Desktop environment, which is provided as the default work environment on many Linux distributions. KDE ( kde.org) is an international free software community, founded in 1996, producing an integrated set of cross-platform applications for desktop. How does commercial Qt licensing work? Do all my developers need to have a valid Qt license? The Qt Company exists to support both sets with the dual offering. The Free Software community has thrived because of these rules, but there are also developers who never intend to observe or cannot comply to these rules, and thus should get a commercial license. The freedoms are non-negotiable and absolute, the freedoms cannot be enjoyed selectively or partially, you also need to pass them to your users.
GPL – All users have the rights to obtain, modify and redistribute the full source code of your application. When selecting an open source license for your project, you contribute to free and open source software development by using Qt under any of the following licenses: LGPL version 3, GPL version 2 and GPL version 3.īasic Premises of the Qt Open Source Model