It says that they did drop some APIs. > Qt 6.0 does drop Qt Script and also removes Qt Multimedia / Qt Bluetooth / Qt Virtual-Keyboard modules until a later Qt

It says that they did drop some APIs. > Qt 6.0 does drop Qt Script and also removes Qt Multimedia / Qt Bluetooth / Qt Virtual-Keyboard modules until a later Qt6 version. So I guess it is major if you use those APIs.