My name is Jesper Pedersen, I work for the consulting company KDAB, which have specialized in Qt for the last 15 years.
One of the services we do is help customers migrate to Qt. Over the last six month we have updated our tools for this to support migrations from Photon to Qt.
In the process of this I recorded a video describing the process of doing a migration. You can find the video here: youtube.com/watch?v=I3GkDHwAvaU
Even if you do not decide to use our service, the video contains lots of valuable hints for those of you considing a migration yourself.