The Samsung Galaxy S6 flagships say, "So long, and thanks for all the fish!"
The Samsung Galaxy S9 devices were released just over a month ago. While the new devices represent another generation of Android smartphones—and offer the latest technology Samsung has for the smartphone industry—they also signal the demise of older devices. Obsolete is the best adjective for describing the Samsung Galaxy S6 lineup of devices, as Samsung has now officially dropped all software support for the devices, signaling the end of life of the flagships.
The devices in question are the S6, S6 Edge, S6 Active, and S6 Edge+. The S6 was released in March 2015, so this is exactly three years since its first hurrah. Samsung usually provides its flagships with monthly security updates for a period of three years, and two major updates. Other devices from the OEM usually get one major update, and quarterly security updates for a period of two years.
There were rumors that the S6 would receive an update to Oreo but those turned out to be false. Users of the listed devices would do well to install a custom ROM with better support, or switch over to a newer model.
Do note that the Note device of that generation, the Note 5, was launched in August, so it will continue receiving updates for the next four months.