Just over a year ago, Spotify reported Apple to the EU competition authorities, on the grounds that the company intentionally disadvantages other app developers in order to promote its own services.

In an interview with Bloomberg TV, Spotify's CEO Daniel Ek says that while it's moving in the right direction, it will take time before he can consider Apple's platform as open and fair.

The big stumbling block concerns the 30 percent fee for subscriptions taken through Spotify's iPhone and iPad app. As a result, Spotify has raised the price for these users.

On other issues, Apple has reached an agreement with Spotify, which has led to the popular music service now being available for Apple TV, where playback can be controlled with the help of Siri. Of course, Apple Music and Spotify remain rivals.

Apple recently signed an agreement with Amazon that will prevent that company from paying the 30 percent fee for movies and TV shows sold through the Amazon Prime app, so obviously Apple's rules are not carved in stone.