Qt is licensed under a commercial and open source licenses (GNU General Public License version 3 and GNU Lesser General Public License version 2.1).
We want to make sure that you are fully aware of the license types of Qt and which is the correct one to use based on your development project. It is important that you are in the know of the requirements of developing under the GPL or LGPL. Learn about the LGPL requirements here and the GPL requirements here.
Questions about the Qt commercial license? We recommend you contact Qt by Digia for more information on the Qt commercial license, what it enables and how you can start developing with it. Contact Qt by Digia.