Yes I had a look into it but no time. In short authentification process changed. Most funktion from libspotify doesn't work but as far as I understand it is still needed for streaming or downloading songs.
Spotify does not provide a useful api so you need to mix web api with native api. It is a mess and poor support from spotify. I guess they don't have talented developers or don't like to support the embedded community.
For authentification I wanted to update the qt library. Maybe next holiday I will have another look into it.