Gran Turismo 6 confirms that online services of the PlayStation3-exclusive software “Gran Turismo 6” will be cut off on 28 March 2018 at 12:00 UTC. All available DLC will also stop being sold on January 31, 2018 to prepare for the inevitable closure of the game’s online portion. After March 28, Community, Open Lobby, Quick Match and Seasonal Events will no longer be usable. The offline portions of Gran Turismo 6 will remain playable.
According to Gran Turismo team’s recent blog post:
On 28 March 2018 at 12:00 UTC, the online services of the PlayStation®3-exclusive software “Gran Turismo 6” will come to an end. Prior to this on 31 January 2018, we will also end the distribution of downloadable content that can be used in-game.
After the end period, it will no longer be possible to utilise online services such as the Community, Open Lobby, Quick Match, and Seasonal Events. The offline portions of the game can still be played.
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”.
Warning Regarding In-Game Credits
If you have deleted your game data after purchasing credits from the GT Store, please make sure to install/redeem the credits again before the end of the online service to have them available in-game. The installation/redemption of credits can be done in-game from [My Home] -> [GT Store] -> [Purchased Content]. It will no longer be possible to install/redeem credits after the end of the online service.
How to re-download Credits when your game data has been deleted
Even if you accidently delete your game data after the end of the online service, it will still be possible to re-download and re-install the credits. To re-download them, go to the [Download List] in the PlayStation®Store, or go to [PSN] -> [Account Management] -> [Purchase History] -> [Download List] from the PlayStation®3 XMB (Cross Media Bar).
Regarding the “Track Path Editor”
With the end of the online services, the distribution of the “GT6 Track Path Editor”, currently available on “Google Play” and the “App Store”, will also end as of 28 March 2018. After the end of the online services, it will no longer be possible to transfer track data created with the “GT6 Track Path Editor” to “Gran Turismo 6”.
Source: Gran Turismo 6 News: Gran Turismo 6 Online End of Service