The free update to the mobile app unlocks an 'Extreme' quality mode, which allows iPhone and iPod Touch users to match the highest quality audio mode offered on Spotify's desktop service for the first time on a mobile device.
And while we may not call 320kbps 'extreme' high quality, it's certainly a step in the right direction.
As yet other Spotify mobile apps for the likes of Android and Windows Phone have not been updated, though you'd expect them to follow suit.
To access the new higher quality streams go in to 'Settings' and then 'Stream', where you'll find the 'Extreme' mode.
While Spotify Premium users had already been able to enjoy 320kbps audio on the desktop client, mobile access was limited to 160kbps.