Samsung has decided to downgrade the update policy of Galaxy A6 2016. That is a pretty good move since the device will no more get any major update. But since this device is still 1 year remaining on hand for updates. That means you will still get the security updates for one more.
From the beginning, the smartphone used to receive updates pretty much every month. However, the device is nearly 3 years old, which means Samsung would remove the device from the regular update list. Now, the device is moved to the Quarterly Update policies.
However, be lucky that Galaxy A6 2016 is at least getting the quarterly update, unlike S6, which was removed from the list, once three years crossed.