Directement en provenance de la FAQ (désolé, j'ai pas envie de traduire):
"What kind of licenses exist for Qt?
The Qt toolkit is available under two different licenses: The Professional and Enterprise Editions for commercial use on all platforms, and the Free Edition for developing free/open source software for the X platform.
What are the differences between the Professional/Enterprise Editions and Free Edition of Qt?
You may write commercial/proprietary/non-free software only if you have purchased the Professional or Enterprise Edition. The library itself is the same. With the commercial editions, you also get technical support and upgrades. Qt for Microsoft Windows is only available as Professional and Enterprise Editions.
Can we use the Free Edition while developing our non-free application and then purchase commercial licenses when we start to sell it?
No. The Free Edition license applies to the development phase - anything developed without Professional or Enterprise Edition licenses must be released as free/open source software."
[^] # Re: Licence
Posté par oliv . En réponse à la dépêche Sortie de Qt 3. Évalué à 1.
"What kind of licenses exist for Qt?
The Qt toolkit is available under two different licenses: The Professional and Enterprise Editions for commercial use on all platforms, and the Free Edition for developing free/open source software for the X platform.
What are the differences between the Professional/Enterprise Editions and Free Edition of Qt?
You may write commercial/proprietary/non-free software only if you have purchased the Professional or Enterprise Edition. The library itself is the same. With the commercial editions, you also get technical support and upgrades. Qt for Microsoft Windows is only available as Professional and Enterprise Editions.
Can we use the Free Edition while developing our non-free application and then purchase commercial licenses when we start to sell it?
No. The Free Edition license applies to the development phase - anything developed without Professional or Enterprise Edition licenses must be released as free/open source software."
plus de détails:
http://www.trolltech.com/developer/licensing/index.html(...)
où on lit : "The Qt Free Edition (version 2.2 and later) is released under the Open Source license QPL, and GPL."
et la FAQ simple
http://www.trolltech.com/developer/faqs/simple.html(...)