Frequently Asked Questions

• What is the LGPL?

• Why did you switch to LGPL?
• When will the licensing change occur?
  
• What is the difference between LGPL and GPL?
  
• What versions of Qt will the licensing change affect?
• Does the licensing change apply to Qt Extended (Qtopia)?
• Does the licensing change apply to Qt Creator?
  
• What version(s) of the LGPL will you use?
  
• What platforms (operating systems) does the licensing change apply to?
  
• Will you continue to offer Qt under the GPL as well?
  
• Will you continue to offer Qt under a commercial license?
  
• Why would I want to buy a commercial license?
  
• Will commercial license holders be able to renew their existing licenses?
  
• Will there be different support and services available depending upon the license model chosen?
• Has the pricing structure changed on commercial licenses?
• Will I still be able to buy renewals?
• Can I switch from using Qt under the LGPL to commercial afterwards?
• Can I transition my commercial Qt project to LGPL and how?
• Can I switch from using Qt under the GPL to the LGPL?
  
• Will I be able to contribute to Qt?
  
• What contribution model will you employ?
  
• How does this affect my current open source project/application that is built on Qt?
  
• What does Nokia hope to accomplish with this new strategy?
  
• Will Qt for S60 be available under both a commercial and LGPL license?
  
• The Symbian Foundation has chosen the Eclipse Public License for Symbian – is the LGPL compatible with this?

What is the LGPL?

The GNU Lesser General Public License, or LGPL, is a free software license published by the Free Software Foundation. It was designed as a compromise between the strong-copyleft GNU General Public License, or GPL and permissive licenses such as the BSD licenses and the MIT License. The LGPL places copyleft restrictions on the program itself, but does not apply these restrictions to other software that merely links with the program.

Why did you switch to LGPL?

We have always chosen licenses that best support our goals. Following the Nokia acquisition, our goals have changed from being focused on revenue generation to supporting Nokia’s overall software strategy through the vision of “Qt Everywhere.” The LGPL license will make it easier for developers to adopt Qt. By spreading the use of Qt as widely as possible and establishing a robust ecosystem, Qt will ensure that Nokia devices and services are of higher quality and reach the market in a timely fashion.

When will the licensing change occur?

It will take place beginning with the release of Qt 4.5, which is scheduled for March 2009.

What is the difference between LGPL and GPL?

Both of these licenses are complex documents that require careful reading to appreciate the significant differences between both licenses. However a high-level explanation is that the GPL requires that any derivative work (e.g.: applications developed using Qt) must be relicensed under the terms of the GPL. The LGPL is less restrictive and enables the development of closed source applications. We will be releasing Qt under the LGPL version 2.1 license, plus continuing to offer Qt under the GPL version 3.0.

What versions of Qt will the licensing change affect?

Version 4.5.0 will be the first release of Qt licensed under the LGPL, commercial license, and GPL v3. We intend to release all subsequent Qt releases under the LGPL, commercial, and GPL v3 licenses.

Does the licensing change apply to Qt Extended?

No, the licensing change does not apply to Qt Extended.

Does the licensing change apply to Qt Creator?

Yes, this will include the following Qt tools: Qt Linguist, Qt Designer, Qt Assistant, and Qt Creator.

What version(s) of the LGPL will you use?

We will be using LGPL version 2.1.  We selected LGPL version 2.1 as this is the version of the LGPL that best fits our purposes and we are most comfortable with at this point in time.  We will continue to evaluate the adoption, use and legal interpretation of LGPL version 3 by the community and may use this version of the LGPL for future releases.

What platforms (operating systems) does the licensing change apply to?

We will license Qt under the LGPL for all platforms we currently support. This includes Windows, Linux/X11, Mac OS X, Windows CE, embedded Linux, and the upcoming S60 port.

Will you continue to offer Qt under the GPL as well?

Yes, we will continue to license Qt under GPL v. 3. It is not necessary to continue offering Qt under the GPL v. 2.0. LGPL v. 2.1 permits the conversion of a particular copy of the LGPL licensed software to be converted to the GPL.

Will you continue to offer Qt under a commercial license?

Yes, absolutely.  Our commercial licensing will continue.

Why would I want to buy a commercial license? What is the difference?

The commercial Qt license includes email support, access to upgrades and allows you to develop fully closed source software. 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.

Will commercial license holders be able to renew their existing licenses?

Yes, absolutely. Our commercial license will continue to be available as it has been in the past.

Will there be different support and services available depending upon the license model chosen?

We want to ensure that our customers are successful, regardless of the license they choose. Therefore we will offer technical support and additional services as stand alone products for those who require them.

Has the pricing structure changed on commercial licenses?

No, we will follow the same pricing structure as before.

Will I still be able to buy renewals?

Yes, commercial users will still be able to renew their license and retain access to support and updates.

Can I switch from using Qt under the LGPL to commercial afterwards?

Users of the LGPL versions of Qt need to comply with the LGPL licensing terms and conditions. Qt’s commercial license agreement contains a restriction that prohibits customers from initially beginning development with the LGPL licensed version of Qt and then transitioning to a commercial version of Qt.

Can I transition my commercial Qt project to LGPL and how?

Customers who have developed applications with Qt will be able to dynamically link their proprietary applications to the LGPL licensed Qt library. Additionally, as customers own the modifications they make to Qt under the commercial license, they may relicense such modifications under the LGPL if they wish.

Can I switch from using Qt under the GPL to the LGPL?

No, those using the GPL licensed versions of Qt need to fulfill the requirements of the GPL. You will be able to re-release your work under the LGPL by incorporating it with or using the LGPL licensed version of Qt.

Will I be able to contribute to Qt?

Yes, absolutely. We are working on the final details of our contribution model now, and will announce more details with the release of Qt 4.5.

What contribution model will you employ?

We are currently working on the final details of our contribution model, and will announce more details with the release of Qt 4.5, expected in March 2009. We also intend to continue following our internal policies that require that contributions fulfill a number of criteria, including:

• Passing an API peer review process;
• Ensuring that contributions are properly documented; and
• Assuring that contributions pass regression tests and work across all platforms.

How does this affect my current open source project/application that is built on Qt?

As the LGPL allows the users to change the license of a particular copy to the GPL, this should not have any negative affect on existing projects. It will, however, provide more licensing options for developers. Additionally, Qt will continue to be licensed under the GPL v3.

What does Nokia hope to accomplish with this new strategy?

Our aim is to:

• To establish Qt as the de facto standard for rich UI and application development, ensuring that there is a vibrant ecosystem of application developers for Nokia devices and other platforms
• Ensure that Qt is of the highest quality possible with good supporting tools and services such that Nokia is able to get devices to market faster, and with better software. The widespread use of Qt translates into greater richness and stability across and between platforms.
• By spreading Qt usage as widely as possible and establishing a robust ecosystem, Nokia will gain access to true cross-platform APIs for developing applications and services once, and deploying them across desktops, devices and the web without rewriting the source code.

Will Qt for S60 be available under both a commercial and LGPL license?

Yes. Qt for S60 will be offered under both licenses once it is released. We will not release technology previews, betas or release candidates under the LGPL.

The Symbian Foundation has chosen the Eclipse Public License for Symbian – is the LGPL compatible with this?