Qt Everywhere: 4.5 To Be Relicensed As LGPL

Nokia has announced that starting with version 4.5, Qt will be available under the LGPL 2.1. From the announcement,

The move to LGPL licensing will provide open source and commercial developers with more permissive licensing than GPL and so increase flexibility for developers. In addition, Qt source code repositories will be made publicly available and will encourage contributions from desktop and embedded developer communities. With these changes, developers will be able to actively drive the evolution of the Qt framework.

This exciting change, made with consultation of the
KDE Free Qt Foundation
, should encourage KDE and Qt use among commercial and proprietary developers and makes the philosophy of "Qt Everywhere" complete.

Kai Öistämö, Executive Vice President of Devices at Nokia expands,

"By opening Qt’s licensing model and encouraging more contributions, Qt users will have more of a stake in the development of Qt, which will in turn encourage wider adoption."

The change in licensing for Qt is happening under the mantra "Qt
Everywhere" and is a step to remove any and all possible blocking objections
for not using Qt. Nokia explains further,

Qt will be available under the LGPL version 2.1 with the upcoming Qt 4.5 release. Qt will also continue to be licensed under commercial license terms, as well as the GPL, version 3.0.

Nokia will also be opening up the development of Qt. A clear path for the
extension of external contributions is currently being built, including
publicly available source code repositories and access to the same level of
support, independent of the license.

The simple fact behind this is that Nokia is less reliant on the
income from Qt licensing than Trolltech (now Qt Software) was, and this has
given Qt Software more room to approach the market with more permissive
licensing strategies in order to increase adoption of the Qt toolkit.
This is part of the 10x growth target announced at last year's Akademy
to achieve ten times as many developers and ten times as many free software community users.
Or as KDE and Qt developer Thiago Maciera put it "we want KDE to be ten times as big".

While kdelibs has always been available under the LGPL, this marks the first
time that both Qt and kdelibs will both be available under the LGPL.
This will help make the licensing of KDE's libraries more permissive, flexible
and coherent. KDE's licensing is summarised on href="http://techbase.kde.org/index.php?title=Policies/Licensing_Policy">TechBase,
and can be described as "LGPL or equivalent for libraries, GPL otherwise".

Meanwhile, Nokia reiterates their commitment to a commercially viable and,
technology-wise, best-of-breed toolkit. In fact, the performance and
functionality improvements that can be seen in the upcoming Qt 4.5 release are
impressive. Running KDE 4.2 with Qt 4.5 is already being tested by several
engineers inside Qt software, which has resulted in a number of bug fixes in
both KDE and Qt. Independent of the licensing changes, the KDE release team
plans to update the version of Qt in KDE's development tree (qt-copy) shortly
to snapshots of Qt 4.5 which is due to be released in March.

All-in-all today's news means tremendous things for Free and Open Source software. The
possibility of extending the reach of all of our work is exciting in and of
itself, and this announcement could lead to a veritable explosion of Qt and
KDE adoption.

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by Nikolaj Hald Nielsen (not verified)

Sweet! I was unsure about what the long term implications of Nokia buying Trolltech would be at the time when it was first announced, but this is certainly a very positive outcome!

by patpi (not verified)

There is available FAQ what this change really means for developers/companies:

by I'm off to learn Qt (not verified)

Yes, this is is the optimal license solution! A very open toolkit that allows open and closed applications. I been waiting/hoping for this for years. Now (soon) there is no reason not to use Qt :-) This killed any interest I had in learning gtk...

by Thorben (not verified)

Thanks a lot Nokia!

I'm very excited about this news, Qt is such a great toolkit that everyone should use it :-)


by Paul Eggleton (not verified)

Awesome news! I always understood the reason for Qt's previous licencing policies and never imagined this day would come. Congratulations to Nokia and Qt Software for their investment in the Free Software community.

by Jakob Petsovits (not verified)

This is big. This is big. Dude! (!!)

by patpi (not verified)

This is really huge announcement. It is hard to predict real impact of this decision at the moment but effects of licensing under LGPL and GPL3 will be HUGE for all KDE. I think this really has a great chance to "lead to a veritable explosion of Qt and KDE adoption."

now KDE has everything important:
- open source licence
- possibility to use KDE technology also to gain some money if needed
- cross platform capabilities
- flexible technology from KDE4
- and as always great ideas and contributors

next step really could be world domination. Now only lets convince downstream to use KDE technology as base for desktop development. Everywhere, as base for desktop oriented distributions - I'm looking at you Canonical - , as base for netbooks, as base for enterprises (KDE PIM everywhere ;] ) , etc

I think those news are great ones!

by mahoutsukai (not verified)

I understand what you mean by "now KDE has everything important". Nevertheless, I want to clarify that KDE had all of the points you mentioned already since Qt was released under the GPL on all platforms. The Kolab Konsortium very successfully earns money by extending Kontact with features needed by their customers since more than 6 years. So the "possibility to use KDE technology also to gain some money if needed" exists since a long time already.

The only thing that is new (and that you most likely meant) is that starting with Qt 4.5 and KDE 4.3. one can develop proprietary, closed source software using Qt and KDE without the need to buy a commercial license for Qt.

by Stephan (not verified)

The real benefit for Linux users is that, as others have said, now competition can be solely on technical merits.

That means that integrators no longer have "We can't develop our closed-source corporate offerings in it cost-effectively" as a justification for dismissing Qt and KDE desktops in favor of GTK+ and GNOME/Xfce desktops.

by Brandybuck (not verified)

The LGPL makes a bigger impact in the commercial/proprietary scene, and not as much for KDE. That's because Qt was already Free Software (GPLv3+exceptions). The biggest impact for us, I think, is that it will silence those few critics that claimed GPL+exceptions was not free enough. Now Qt can be compared to GTK+ and other toolkits on the basis of technical merit, instead of mere licensing.

Here's a good overview of the situation: http://www.ics.com/files/docs/Qt_LGPL.pdf

by Norbert (not verified)

But will this mean Nokia will reduce the number of developers working on QT in the hope there will be other people coming up to work on for free?
Especially in hard times like this: no revenue -> less support from upper management -> less people...

A "commitment" from upper management on anything is usually not worth the pixels showing it on the screen...

I hope it will turn out fine...
(Sorry for being a bit negative -> but it wouldn't be the first time)

by Anon (not verified)

I don't think you realise just how profitable Nokia is - they probably spend more on lunches for executives than they do on Qt :)

by Aron Kozak (not verified)

We are actually working actively to hire more developers here at Qt Software.

by Anon (not verified)

Just out of interest - do you know if Nokia is planning to sponsor some more developers to work on KDE itself? It's a great advert for Qt and, considering how far it's come on a shoestring budget, and addition of even 3 or 4 full-time developers could give a huge return on investment.

by KDETroll (not verified)

"It's a great advert for Qt"

NO - Since KDE4 it is exactly the opposite.

by slacker (not verified)

Then all the more reason for Nokia/Qt to spend some money making it better :).

by Thiago Macieira (not verified)

We in Qt Software beg to differ: http://labs.trolltech.com/blogs/2008/12/04/how-kde-4-is-blocking-qt-45/

We respect your opinion, but ours is that KDE 4 is a great showcase. So, we will act accordingly.

by Anon (not verified)

"So, we will act accordingly."

I'm tempted to interpret this as a "yes" to my original question ;)

by Jos (not verified)

No, Nokia will *increase* the number of Qt developers:


Nokia realizes that a good software platform is key to the success of the telephones and Qt is their choice of platform.

Qt Creator is another initiative Nokia has taken to make it easy for developers to start developing for the Nokia platform. The goal is that software created like that will run on Windows, Linux, Mac *and* Nokia phones.

by mat69 (not verified)

I hope they really realize that. There are so many mobilephones that are great. Great if you look at the hardware but if you look at the software many suck so hard that you wonder how they made it to the market.
My mobilephone e.g. can do so _much_ but when it comes to navigating the menus it is slow as hell and sometimes I encounter bugs like shutting it down though there is enough battery power left etc.

A good foundation one can reuse and thus improve and something that would be really used would change a lot.

Imo most people do not want to only look at a phone but also use it, I hope that Nokia will improve the "use" part with this move. :)

by HelloWorld (not verified)

Actually, the situation hasn't really changed for commercial (paying) developers. Although it opens up options for them as well, the commercial Qt license says you cannot use the open source (LGPL or GPL) version of Qt to start developing a commercial program, and then switch to the commercial license.

So that means commercial developers still *need* to pay for a commercial license if they don't want to be "stuck" with the LGPL or GPL licenses for their programs.

by Jakob Petsovits (not verified)

True, but on the other hand, there's not much to be "stuck" about with the LGPL. It offers most freedoms that even proprietary developers would require, you just can't modify Qt itself without releasing those changes into the wild.

But that's about the only thing where you're "stuck" with the LGPL, there's now little reason to buy a license unless you need the commercial support services. I would be interested in the reasons that you consider important enough so that developers "still *need*" to buy a license.

by Knut Yrvin (not verified)

When creating a device that will include LGPL and proprietary components, you need to ensure that you comply with the following restrictions in the LGPL:

-- Modifications made to the library itself must be licensed under the terms of the LGPL

-- A proprietary application that is a “work that uses the library” needs to be dynamically linked with the library in order to avoid becoming a combined work that results in a licensing incompatibility

-- Users need to be aware that an executable might be a combined work with the library unless a suitable shared library mechanism is used (i.e., one that, at runtime, uses a copy of the library already present on the user’s computer system (rather than copying library functions into the executable), or one that will operate properly with a modified version of the library (if the user installs one as long as the modified version is interface compatible with the version that the original was made with).

Yes, this license incompatibility is a serious issue. IMHO, the FSF has a point, but in some cases they are shooting themselves in both feet, and it is hurting Linux.

Clearly, the nVidia drivers are illegal under any type of GPL and there are issues with printers where there are proprietary parts of the driver that can not be LGPLd or GPLd. Then there is the ZFS which Linux can't use in Kernel space.

Basically, I can see why linking to non-free software should be forbidden in general, but why should the LGPL and GPL forbid linking to other libraries which are free and open -- free and open software being any software where you can get the source code for free.

Then there need to be exceptions. How should the FSF licenses handle things like the Epson printer drivers. They are free and you can download the source code, but it comes with binary libraries. If the binary code is available free, that isn't as free as if you could get the source code (it isn't open), but free is free and the FSF license being pickey about minor points is not advancing the cause of FOSS. There should be exceptions in the LGPL & GPL for other types of free software. Whether or not the software is free (as in beer), is more important than the details of the license. That is my $0.02.

by Stephan (not verified)

Even without being as much a zealot as RMS, I can still understand the problem with that. There's no guarantee that code will remain ABI compatible as systems march onward. Windows provides that guarantee to some extent, but a big part of Linux's architectural strength comes from an assumption that old APIs and ABIs can be phased out and new ones phased in.

GPLing the kernel, for example, ensures that anything legally distributed as a part of it will have source code that can be adapted to new hardware platforms or to satisfy new requirements. The kernel's API is probably one of the least stable APIs on a linux system, but even more typical stuff changes. For example, the ABI for libstdc++ changed a couple of years ago and now, only a handful of apps require the old version of libstdc++ to be installed.

I don't see your point. Obviously it wouldn't apply to software that was open but not GPL since the source code would be freely available. This is the main issue is whether the GPL should forbid linking to other types of open software.

There are serious issues with the ABI of the nVidia Kernel drivers and having a GPL Kernel doesn't solve them.

I suggested that there be a singular exception that GPL or LGPL code be allowed to be combined with binary libraries. Since there is no alternative in the case of printer drivers, the problems are simply something which we would have to live with. In this case, the problem you mention is very unlikely to occur since the ABI (to either GhostScript or GIMPPrint) is in the GPL part of the code.

by Curious (not verified)

PLease explain to me what (as long as I don't want to alter the Qt libs) is the difference to me as a closed-source developer between the LGPL and commercial licences in effect. As I read it I can distribute my code completely closed if I use either of those licenses?

by boudewijn (not verified)

The difference is a certain amount of money and a good deal of support.

by Thiago Macieira (not verified)

Obviously this is not the place for legal advice. You should read the LGPL or have a lawyer interpret it for you, so you don't expose your business to unnecessary risk.

The LGPL is more liberal than the GPL, sure, but it's still a far cry from "free, free, free". There are still obligations to fulfill, limitations, etc. The most mentioned one is the relinking clause.

In the end, we expect to a certain switch from commercial, closed-source applications to the LGPL, closed-source model. And we expect there to be creation of Qt applications directly into the LGPL/closed-source model (the "shareware / freeware market" that we previously didn't address)

by Brandybuck (not verified)

If all you do is dynamically link with Qt, then you can use LGPL Qt for your proprietary projects. But it doesn't apply to static linkage, modifications to the library itself, and some other cases. Also, Qt Extended (Qtopia) remains GPL. I think most embedded developers will stick with the commercial license, as well as a few application developers.

by kubunter (not verified)

> Also, Qt Extended (Qtopia) remains GPL.


"Nokia today announced that its Qt cross-platform User Interface (UI) and application framework for desktop and embedded platforms will be available under the Lesser General Public License (LGPL) version 2.1 license from the release of Qt 4.5, scheduled for March 2009."

by Brandybuck (not verified)

Qt != Qt Extended

Go read the FAQ: "Does the licensing change apply to Qt Extended?
No, the licensing change does not apply to Qt Extended." My interpretation is that Qt (included Qt/Embedded (previously known as QtopiaCore)) will be LGPL, but that Qtopia Platform (Qt Extended) will remain Dual/GPL.

by Kolla (not verified)

Yeah, well... but who cares about that POS?
Seriously, Qtopia only makes me depressed.

by T. J. Brumfield (not verified)

What I've been waiting for is for Nokia to release a killer piece of hardware to showcase Qt and KDE as a fully-featured mobile computing platform.

I keep drooling over the n810 tablet, but it doesn't have enough memory. The n96 is big, clunky, and doesn't have the resolution necessary to run decent apps (not to mention really expensive, and runs Symbian)

If Nokia were to unleash a new smart phone and/or tablet with a high resolution OLED screen and decent memory (like the rumored G2 specs, and the rumored iPhone HD specs) and showcased KDE 4 and Qt running on top of it, I think Nokia could get back in the game.

by Kolla (not verified)

If Nokia wants to get back in the game, they should stop dicking around and deliver phones with operating system that actually works well (as in stable), are easy to set up and use (not that damn inconsistant and confusing menu hell of S60v3), quick and responsive UI, rotate between apps using single tap/key input, dont crash because of third party apps etc. etc.

I dont see KDE4 solving anything here, it's way too bug ridden to be of any use on a phone, and plasma would eat out the battery.

by T. J. Brumfield (not verified)

Yet KDE4 runs on the Nokia n810 with minimal memory.

by Anon (not verified)

"Runs" is being rather charitable, I think: "hobbles" might be more accurate.

by jospoortvliet (not verified)

Most of KDE wouldn't really be useful on a phone, but Plasma would be. And saying it would drain your battery - hah! If I run powertop on my laptop, I see firefox, firefox and firefox. And I run plasma with lots of applets, compositing kwin and a bunch of KDE apps. Numbers are even better:
Wakeups per second:
Firefox: 139 + 14.9 (shows up twice)
KWin 9.4
Plasma 4.2

when I close firefox, my powerusage drops by 3 watt (acer aspire one)...

I doubt using plasma on mobile devices and things like the N810 would INCREASE poweruse. I actually expect it to go down.

by Brandybuck (not verified)

Nokia/Trolltech is busily hiring new engineers. Their goal is "Qt Everywhere", to make it the expected infrastructure for software development. You don't get there with fewer developers. The engineering focus will still be there.

by Norbert (not verified)

Cool, thanks for all your answers...

by Eric Laffoon (not verified)

Hard times? Nokia paid 100 million Euros for Trolltech. Why? So they could give it away? So they could rake in license fees?

I saw the new head of Qt software speak at last years KDE conference and I don't think I could have been more impressed that someone could be honest, intelligent and totally familiar with the business aspects while being sincerely interested in being a good part of the community. However the true test of a buyout is to see how the employees deal with it. On that count I can only say if I wanted to work full time on software I'd be hitting them up.

What is a commitment worth? See for yourself. No sane company says one thing, does another and expects to stay at the top of their industry. Nokia has made it to the top of several industries and as an 100 year plus company they didn't start with cell phones.

As to their reasons for buying Qt. Clearly it fits in their strategy for having the best tools available and for advancing a technology climate where they are riding the crest of the wave and not following the pack. This move is EXTREMELY logical for them.

by kdefan (not verified)

I think this solves the license issues for a Qt-plugin for SWT and wxWidgets. This means we could probably see a few more well integrated applications on the KDE desktop. Yeah!

by Lee (not verified)

Oh, wow --- is that THAT why wxWidgets never supported Qt? I see :)

Anyway, yes, this is great news. Not only will it make Qt and KDE more attractive to corporate users, it might boost development for both, encourage more cooperation and code sharing with GNOME, etc. Great stuff.

by Roberto Alsina (not verified)

There's also that Qt already is a C++ API and much nicer than Wx to boot. It's like wrapping a faberge egg with an old newspaper.

by Brandybuck (not verified)

With a LGPL Qt, there's absolutely no reason to use wxWindows that I can think of, other than just refusing to learn something new.

by Alex (not verified)

QtCore being GPL was also a problem for system-level libraries, like e.g. libdbus, libz, libpng etc.
E.g. if libdbus would have used QtCore, no closed source application could have used it without buying commercial Qt licenses.
Qt 4.5 being LGPL solves this issue :-)

This is really great news ! :-)


by Ian Monroe (not verified)

libdbus doesn't use Qt due to the license, given that it doesn't even use glib. Its just designed to be a very low-dependency system library.

by Alex (not verified)

Yes, it was just some example.


by Kevin Krammer (not verified)

> is that THAT why wxWidgets never supported Qt?

More likely because nobody with good knowledge of both wanted to spend time on this for very little benefit.

Same for SWT.

A common misconception though, usually comes up when Qt licence changes or is discussed

by Lobotomik (not verified)

"No"? Wow, that answer surely sounds well documented.
"More likely nobody wanted..?" I see, you don't have the faintest clue, or live in refusal of the fact. But don't you worry, it's over now.

I once read in wxWidget's webpage that the reason there could be no Qt version was that it was a way around Trolltech's barrier against proprietary software that used Qt without paying the license, and that as such it could make them incur in Trolltech's legal rage.

Now wxWidgets can have a Qt version with no legal ifs. We'll see if they bother.