Sony is slated to release new firmware for HAP-Z1es and HAP-S1 music servers with update to its HDD Audio mobile app to support Spotify Connect. Although Spotify streams at max. 320kbps on a Premium plan (not hi-res), this is still a major feature enhancement. To tap into Spotify's enormous music library, users have three options; free with ads, $9.99 for an individual premium plan and $14.99 family.
In addition to Spotify, the mew firmware adds compatibility for USB hub via the single EXT USB port on the back of the music server. This allows the user to have CD disc drive and a hard drive to be connected at the same time. A disc drive is used to Import CD to the music server's internal or external hard drive.
Be on the look out for the new firmware within the music server in the Settings/Network Update menu. (source)