Apple has “discontinued” the technology that allows Spotify to control volume from connected iOS devices. The two tech firms’ war wages is on as the streaming giant has confirmed it is looking for a “solution” to the Spotify Connect issue. It does not impact Bluetooth or AirPlay connections, but iPhone users won’t be able to use their volume buttons to turn their tunes up or down and will have to go into the app. Spotify said: “Apple has discontinued the technology that enables Spotify to control volume for connected devices using the volume buttons on the device. While we work with them on a …