Revised versions of the gnu lesser general public license. The lgpl provides an alternative license that preserves many of the benefits of the gpl model for such librariesin fact, the lesser general public license was in its first incarnation known as the library general public license. The lgpl license allows an application that references the binaries to remain closedsource. The lgpl carries some restrictions regarding the ability for users to relink libraries and other restrictions that may impose architectural requirements that some organizations might not be comfortable with. Jun 27, 2019 for example, you deploy your app on 21 june 2017 using commit 5b0427c, but when your user use your app on 20 july 2017, the latest version of therecipeqt is 4e40d6b, so your user want to change his app, on his own, to use the latest version of therecipeqt. For example, if i use the qt open source to make a program and try to sell it, do i still have to pay for the license. Pyqt5 is available under a gpl or commercial license, and pyside2 under a lgpl license. Most commonly gplv2 or any later version is stated by users of the license, to allow upgrading to gplv3. On the qt website you can find obligations of the lgpl. Other applications have licensing requirements that dont play nice with gpl, lgpl or qts commercial license. The version numbers diverged in 1999 when version 2. So im remaking a product and was approaching qt about the.
The commercial qt license includes email support, access to upgrades and allows you to develop fully closed source software. Jan 14, 2009 5 thoughts on qt to be available for free under lgpl n. Qt contains some code that is not provided under the gnu lesser general public license lgpl or the qt commercial license, but rather under specific licenses from the original authors. See how to choose a license for your own work for general recommendations about choosing a license for your work the gnu project has two principal licenses to use for libraries. You may copy, distribute and modify the software provided that you state modifications and license them under lgpl2. Commercial licensing of products such as qt for industrial. Can i develop with commercial qt and install qt creator to more than one of my computers. We recommend that programs that use qt also acknowledge these contributions, and quote these license statements in an appendix to the. So im remaking a product and was approaching qt about the commercial version. Later you seek investment on the basis that you own your own ip.
We recommend that programs that use qt also acknowledge these contributions, and. I dont have enough money to buy commercial license. At qt day 2019 in florence, italy, i gave a presentation about using qt under lgplv3. Qts open source license gpl or lgpl open source stack. Lgpl which qt is released allows commercialclosed source applications as long as you do not modify the qt libraries or if you do making them available to the public. If you intend to develop software using the qt framework, you will need a license commercial or open source. Qt tools and some libraries are only available under gpl.
Most likely all developers were instructed to answer ianal, please contact our legal department. Anything statically linked to the library can only be redistributed under lgpl, but applications that use the library. Both gpl and lgpl do not put any restrictions on selling the applications, you can sell your app, moreover you can sell qt as well and your customers can do it, too. Qt licensed under commercial licenses are appropriate for development of. An example is if you are in a startup and you build software using lgpl qt. Besides the lgpl license for pyside2, youll have to make sure that you comply with the qt licensing terms. Qts commercial license is for when you wish to modify qts source code, and not release the changes you have made to the public.
The license allows developers and companies to use and integrate a software component released under the lgpl into their own even proprietary software without being required by. The gpl makes sense for tools, as it ensures that anyone distributing a modified version gives the changes back to the community, but doesnt prevent using the tools to create nonfree software. A lesser general public license lgpl is a license for opensource software that allows for provisions for including elements of free software in either free or proprietary software. As a special exception to the gnu lesser general public license version 2. The key difference in the two versions in fact the entire reason pyside2 exists is licensing.
Jun 04, 2019 qt for python is available under the lgpl v3 and the qt commercial license. Also, theres nothing preventing you from selling an open source app on the microsoft app marketplace. The commercial qt license gives you the full rights to create and distribute software on your own terms without any open source license obligations. But, fortunately for embedded industrial developers wanting to use lgplv3 licensed software, the definition of user product. I need to use qt and i choose to use lgpl license for qt in my app. I worked for trolltech, and then later nokia who bought t. If you are using the commercial version of qt, or planning to use it, please contact the qt company. However you must license qt under the lgpl and discharge your.
If you are developing opensource software, for the most. For example, you deploy your app on 21 june 2017 using commit 5b0427c, but when your user use your app on 20 july 2017, the latest version of therecipeqt is 4e40d6b, so your user want to change his app, on his own, to use the latest version of therecipeqt. If you are making an application under a different license for example, a commercial application, you have to be careful to meet the requirements of lgpl andor gpl. Lgpllicensed libraries can be linked with nongpl licensed programs, including proprietary software. Jul 20, 20 using the digia qt framework lgpl for commercial applications july 20, 20 july 20, 20 baltazaar this post is targeted at any developer that needs a good framework to develop true cross platform applications. For business a practical guide to open source software licensing. Youve already got the answer that lgpl libraries can be used in commercial software. The gnu lesser general public license lgpl is a freesoftware license published by the free software foundation fsf. With the commercial license you also have access to the official qt support and close strategic relationship with the qt company to make sure your development goals are met. How to distribute qts application cutycapt on windows. Its not permitted to mix qt commercial licenses with qt lgpl licenses in one project. Today nokia announced that the crossplatform qt framework is to be released under the lgpl, with no developer licensing fees or royalties.
When your investors do due diligence you might not have all the legal protections in place in time for due diligence to complete. The lgpl is inappropriate for statically linked software and the commercial license costs money something that many are unwilling to pay. Lesser general public license is sometimes referred to as library gpl or gnu libraries, and some associate it with the idea of. Free and open source software foss is software that comes with a license that. Can i use qt lgpl license and sell my application without. Additionally, the examples included with qt are provided under the terms of the. I will distribute with my app such libraries as qtcore4. The qt development tools and related applications like the qt creator ide will be released under the gplv3 as well as a commercial license.
Nokia announces that its qt crossplatform user interface and application framework for desktop and embedded platforms will be available under lgpl lesser general public license version 2. The gnu project has two principal licenses to use for libraries. The price for a commercial qt license varies depending on the size of your company and your application. Most qt modules are licensed under the lgpl, but some are available under only the gpl. The thing is, pyside2 is for using the qt framework with python programs. License lgpl version 3 is appropriate for the development of qt applications. Jan 18, 2016 the qt development tools and related applications like the qt creator ide will be released under the gplv3 as well as a commercial license. Qt for application development is also available under gpl and lgplv3 open source licenses. Why you shouldnt use the lesser gpl for your next library. The qt company gratefully acknowledges these and other contributions to qt. Qt licensed under the gnu lesser general public license lgpl version 3 is. Track in fossa gnu lesser general public license v2.
The aim of this article is to clear up some of that uncertainty. Documentation contributions included herein are the s of their respective owners. The gnu general public license gnu gpl or gpl is a series of widely used free software licenses that guarantee end users the freedom to run, study, share, and modify the software. Licensees holding valid commercial qt licenses may use this file in accordance with the commercial license agreement provided with the software or, alternatively, in accordance with the terms contained in.
The qm modeling tool uses the qt toolkit under the terms of the gnu lesser general public license v. This is due to a restriction in the qt commercial license on creating applications that pass on functionality which makes it possible for others to create software with the licensed qt libraries. The legal department will tell you buy our commercial license, its the only option. I think the fact that qt cannot be statically linked under the lgpl license will still leave room for wxwidgetsit would be nice if qt could be statically linked and i would then change over. As someone who has been using qt continuously for the last 9 years, this is of particular interest to me. However you must license qt under the lgpl and discharge your responsibilities under that license. Qt to be available for free under lgpl successful software. Qt is available under the following free software licenses. Instead of open files, add files and so on, audacious should have icons. Qt contains some code that is not provided under the gnu lesser general public license lgpl or the qt commercial license, but rather under specific licenses from the original authors the qt company gratefully acknowledges these and other contributions to qt. Licensees holding valid qt commercial licenses may use this document in accordance with the qt commercial license agreement provided with the software or, alternatively, in accordance with the terms contained in a written agreement between you and nokia. And, if you deploy your qt application on an embedded device, you must. The free software foundation may publish revised and or new versions of the gnu lesser general public license from time to time. Qts lgpl license relates to qt and qt only, so you can package your code and license it however you like, but unless you plan on buying a qt commercial license, you have to dynamically link to qt.
The documentation provided herein is licensed under the terms of the gnu free documentation license version 1. According to lgpl license, you have to comply with his wish. Other applications have licensing requirements that dont play nice with gpl, lgpl or qt s commercial license. Qt licensed under commercial licenses is appropriate for development of. Gnu lesser general public license usage alternatively, this file may be used under the terms of the gnu lesser general public license version 2. Qt examples are available under commercial licenses from the qt company, and. The gpl, lgpl, and mozilla licenses understanding open. For example, you can make available the qt sources on your website or on. The licenses were originally written by richard stallman, former head of the free software foundation fsf, for the gnu project, and grant the recipients of a computer program the rights of the. This is due to a restriction in the qt commercial license on creating applications that pass on functionality which makes it possible for others to. Jun 08, 2016 qt asthecompany has always made it very clear that you cant switch your qt lgpl gpl project to a commercial one if you didnt start with the commercial qt license from the beginning. Most of qt is available under lgpl, but some modules are gpl only. If you use qt under commercial license, nothing has changed for you. In compliance with lgpl, this document collects the relevant information about downloading, installing, and building the qt toolkit from sources.
It would fall under the definition of a work that uses the library. Especially since the hefty annual renewal fee for my commercial qt licence is due in a few months. Even modules like the virtual keyboard, the software renderer for qml without opengl and the unittest integration into qtcreator will become available under gpl. Using the digia qt framework lgpl for commercial applications. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. See how to choose a license for your own work for general recommendations about choosing a license for your work. Can i use an lgpllicenced library in my commercial app. I have a piece of software, that i would like to license and protect but i am having a hard time finding the right license, and how i would go about with it. This is at least the stated goal of the qt company. You may copy, distribute and modify the software provided that you state modifications and license them under lgpl 2. Most commercial software comply simply by dynamically linking to qt. We recommend that programs that use qt also acknowledge these contributions, and quote these license. It is very dissapointing however to see absolutely no help from people who work in qt on the lgpl subject. Qt commercial license agreements is available in the qt licensing overview.