Samsung has started pushing out a new update to the Galaxy A8 Duos smartphone from last year. Weighing in at 890MB and hitting units in India, the update brings along Android Marshmallow (version 6.0.1) and also includes Android security patch for the month of September. As is usually the case with OTA roll-outs, it may take some time for the update to hit your device. Meanwhile, if you feel impatient, you can manually check for the update by heading to your handset's Settings menu. Via
Source: http://www.gsmarena.com/firstgen_samsung_galaxy_a8_duos_starts_receiving_marshmallow-news-20857.php