My application links against both qt4 and qt5 libs

[ChrisW67]

I cannot see that KDE has anything to do with this: you are not linking to any KDE library in the snippet you show.
Chances are that the phonon and QJson libraries you have asked CMake to find and link have been built with Qt4. Build and link to Qt5 versions or use the Qt5 equivalents.

[jiveaxe]

I cannot see that KDE has anything to do with this: you are not linking to any KDE library in the snippet you show.

My intention was to remove qt4 and leave only qt5 stuff and see if it compiled correctly.

Chances are that the phonon and QJson libraries you have asked CMake to find and link have been built with Qt4. Build and link to Qt5 versions or use the Qt5 equivalents.

This should be the real problem. I already compiled phonon4qt5. For QJson I read that Qt5 has native support for json, so no need of external library. But I'm stuck converting QVariantMap in json QByteArray (I can't find something like QJson::Serializer)...

EDIT: Never mind. Found right way

Thanks for your help