Sony Mobile released the Sony Marshmallow Android Concept for Xperia Z3 and Z3 Compact earlier this month. It is now in the process of rolling the first OTA update for the Android 6.0 Marshmallow concept. The latest update arrives in the form of build number MRA58K.Z1.2085.
Changes in the latest version include the addition of double tap to wake, MIDI support via USB, an updated keyboard and the support of more bitrates for flac audio. The update should slowly be rolling out over-the-air over the coming days.