[Grishnakh]

Ok, but if you stick with dynamic linking and don't insert Qt code into your app, then you don't need a commercial license, right? Why would you insert Qt code in your app anyway? That kinda defeats the point of using a library. As for static linking, why would you opt for this over dynamic linking anyway? Dynamic linking is better since other applications can share the libraries. Static linking on a PC platform is basically a hack for poor library management.

As for Qt for Device Creation, I looked through that and didn't see why you'd need a license there, unless they're selling optional components or plug-ins which are not LGPL licensed (which appears to be the case with things like "Qt Quick 2D Renderer" and "Qt Virtual Keyboard").

I even tried out the questionnaire at www.qt.io/download: if you select "Commercial deployment" for development and then say that you're doing dynamic linking, don't have any concerns about reverse-engineering, and can comply with the LGPL, it recommends you use the open-source LGPL'ed version.

[distances]

Just listing some possibilities, different projects have different needs. Sure, for most of the cases the dynamically linked open source version works just fine.

Qt for Device Creation needs a license, that one is not available as LGPL. Of course you can use the open source Qt yourself for that, but then you'll be facing a lot of platform work to get Qt running on your device before even starting with the stuff that you actually want to build.