3.8. Do I need to worry about LGPL when using a commercially licensed version of Qt?

Usually, not. When using the commercially licensed version of Qt, we provide almost all of Qt under a commercial license terms.

A few modules in Qt, however, use code from the WebKit project licensed under LGPLv2.1. These modules are Qt Script, Qt WebKit and Qt WebEngine. So when using these modules, you will need to fulfill the license obligations of LGPLv2.1 (but not LGPLv3).

Please also note that you can avoid using Qt Script, as the Qt Qml module contains a fully functional JavaScript engine that can be used instead. This module is available under commercial licensing terms and doesn’t introduce a dependency to LGPL licensed code.

As a commercial license user, in practice, you only need to consider license obligations of LGPLv2.1, and only if you make use of Qt WebEngine or Qt WebKit .