As expected of older devices, Samsung has officially dropped support for the Galaxy Note 5 and Galaxy S6 series over two years ago. In a surprising move, the company releases a new firmware update for the two lineups. Samsung started the rollout for the devices in South Korea, with other regions getting the update as well. It isn't clear what the firmware update fixes, but it could be that there's a vulnerability affecting these 2015 flagship models.
Source: SamMobile