Products distributed under the commercial version of Qt must also be developed under the commercial version of Qt. If you have already started the development with an open-source version of Qt and wish to move to a commercial license you need to have a written explicit permission from The Qt Company to facilitate this change.
The Qt Company reserves the right to grant the permission at its own discretion. If you are unsure of which license or version to use when you start development, we recommend you contact The Qt Company to advise you on the best choice based on your development needs. Yes, it is possible to use both LGPLv2. Doing this does not require changing license in either of the libraries, and it is possible to select a proprietary license for the application, if desired.
If LGPLv2. KDE is an international free software community, founded in , producing an integrated set of cross-platform applications for desktop and mainly known for its Plasma Desktop environment, which is provided as the default work environment on many Linux distributions.
KDE software is based on the Qt framework. In the early days of Qt, the KDE project and community was the biggest driving force in building the developer ecosystem around Qt. In the very early days, Qt was already dual-licensed, but the source code was available under proprietary open source licenses.
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 bought or go bankrupt. The license agreement has been updated couple of times over the years, mainly because of acquisitions around Qt or updates to licenses and platforms. If software using these open source licensed libraries does not fully comply with the license obligations you will lose your license and related distribution rights.
It depends on how you license and distribute your product. You will need to fulfill the license obligations for these licenses when using Qt in your product. Both licenses have the same intention, namely to protect the freedom of users to use and modify the software licensed under LGPL. LGPLv3 makes this intention very explicit.
You have to provide means to the end user to install a modified version of the library licensed under LGPLv3 and run your software using that modified library. In practice, this for example refers to:. The above freedoms cannot in any way be restricted by other licensing terms. If an application is not fully following all the obligations as outlined above, it is not allowed to be distributed at all.
Usually, not. When using the commercially licensed version of Qt, we provide almost all of Qt under a commercial license terms. So when using these modules, you will need to fulfill the license obligations of LGPLv2. Please also note that you can avoid using Qt Script, as the Qt Qml module contains a fully functional JavaScript engine that can be used instead.
As a commercial license user, in practice, you only need to consider license obligations of LGPLv2. In case there is any doubt on whether the requirements of the open source licenses can be met in full, the commercial licensing option of Qt is often the best choice to avoid legal setbacks. Qt for Open Source Development Before proceeding to download Qt for open source development make sure you are choosing the right license for your project. What to Consider The Qt framework is available under both open source and commercial licenses.
Please note that it's not allowed to use both open source and commercial licensing in the same application or device. Visit the Qt licensing FAQ to learn more. Your Contributions Matter Since our funding comes from selling commercial licenses and services, it is essential that we reach commercial readiness as quickly as possible.
Qt has an online marketplace, featuring primarily free Qt extensions, including those produced by the KDE community. To learn more about what can be accessed, and even to host your own content, visit the Qt Marketplace. Get Started. Looking for Qt binaries? Frequently Asked Questions. Use of open source licensing gives users four primary degrees of freedom when using Qt applications or devices: The freedom to run the program for any purpose The freedom to study how the program works and adapt it to specific needs The freedom to redistribute copies so you can help your neighbor The freedom to improve the program and release your improvements to the public, so that the whole community benefits The Free Software community has thrived because of these rules, but there are also developers who never intend to observe these rules, and thus should get a commercial license.
Please refer to section 2. Please refer to question 2. In practice, this for example refers to: Tivoization — Explicitly not allowing creation of closed devices where the end user does not have the LGPL granted rights for the Qt open source libraries DRM and hardware encryption — This cannot be used to circumvent these obligations Software patent retaliation — Where all users of the software are granted licenses thus making software patent retaliation of any potentially patented software in the distributed software meaningless.
Windows Host. Qt Creator 5. If you need a standalone installer, please select the file according to your operating system from the list below to get the latest Qt Creator for your computer.
The source code is available as a zip 69 MB Info or a tar. Be sure to check if Qt is supported on your platform and read the installation notes that are located in the Qt Documentation. Looking for Qt 6. Source packages are here. Looking for Qt Creator 6. It can be found from here. Offline Qt Downloads. Qt6 source packages 5. Qt6 Source Packages Qt 6.
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