Samsung Galaxy A8 (2015) getting Android 6.0.1 Marshmallow update, only dual-SIM model
It's understandable that Samsung wants customers who purchased its flagship smartphones to be up to date with the latest Android releases coming from from Google, but there are more consumers who own mid-range handsets which are usually getting updates very late.
If you own the Galaxy A8 (2015), then you should know that the update is only available for the dual-SIM version. Dubbed Samsung Galaxy A8 Duos, the smartphone was released in India last year, at the same time as the single-SIM model and running a similar version of the OS.
It's also worth mentioning that the update is about 890MB in size, so make sure your phone is connected to a stable Wi-Fi network to avoid mobile data charges. Keep in mind that the OTA is pushed in stages, so it might take a few days to show up on all Galaxy A8 Duos devices.
Things that are NOT allowed: