On the official Gran Turismo website, a notice can be found regarding the end of the online services for Gran Turismo 6, the 2013 racing simulator for the PlayStation 3.
The online services, as mentioned on the website, will shut down next year on the 28th of March. This means all online functionalities will cease, such as the Community, Open Lobby, Quick Match, and Seasonal Events.
In addition, all distribution of DLC will end by January 31, 2018, but any DLC purchased before that will still be able to use offline, along with the single-player of the game.
Polyphony Digital has a few words for the players, "We would like to thank the many users of the Gran Turismo 6 online service since its first launch in 2013. From here on, we will continue to further improve the online services for the currently available title “Gran Turismo Sport”.
Polyphony Digital is actively working on their newest release, Gran Turismo Sport, which is currently available on PlayStation 4.