[77pt77]

You can use almost all of QT even in close source, provided you only link dynamically.

[atq2119]

I'm pretty sure you could even link statically, as long as you provide the necessary .a / .o files to rebuild against a different version of the LGPL library. But of course dynamic linking is the safer approach.

[77pt77]

I believe you are correct.

You'd have to provide a way to relink.

I seriously can't see a judge ever being able or willing to understand what's at stake here in case this ever gets to court.