The Pokémon Global Link for XY and ORAS will close in late October 2016 but will be upgraded to support Pokémon Sun and Moon.

Press Release - Closure of the Pokémon Global Link service for Pokémon Omega Ruby, Pokémon Alpha Sapphire, Pokémon X, and Pokémon Y

With the release of Pokémon Sun and Pokémon Moon, the Pokémon Global Link (PGL) will end its current Pokémon Omega Ruby, Pokémon Alpha Sapphire, Pokémon X, and Pokémon Y service. The PGL service will be updated to work with Pokémon Sun and Pokémon Moon.

After the current PGL service ends, you won't be able to link Pokémon Omega Ruby, Pokémon Alpha Sapphire, Pokémon X, or Pokémon Y with the PGL, or see data from these games reflected on the PGL. However, you will still be able to use the other non-PGL services via the Internet. Please see the following "Services" section for details.

We thank you very much for enjoying the current PGL since October 2013. We hope you'll have fun in the updated PGL! End date of the Pokémon Omega Ruby, Pokémon Alpha Sapphire, Pokémon X, and Pokémon Y PGL service Planned for late October, 2016

• New registration of a game is still available until the current service ends. However, please note that the service that works with Pokémon Omega Ruby, Pokémon Alpha Sapphire, Pokémon X, and Pokémon Y will end, and you won't be able to use various features.
• You can't transfer Poké Miles from the Pokémon Omega Ruby, Pokémon Alpha Sapphire, Pokémon X, and Pokémon Y version of the PGL to the Pokémon Sun and Pokémon Moon version of the PGL.
• If you use Game Sync, the message "The service has been discontinued. (Error Code: 090-0211)" will be displayed.
• You can keep trading Pokémon at the Global Trade Station (GTS), but you won't be able to see your trading log on the PGL.
• After the current service ends, you won't be able to participate in Random Matchup Rating Battles with Pokémon Omega Ruby, Pokémon Alpha Sapphire, Pokémon X, and Pokémon Y.
• Even after the current service ends, you'll be able to keep enjoying the features of Pokémon Omega Ruby, Pokémon Alpha Sapphire, Pokémon X, and Pokémon Y using the Internet, such as Random Matchup Free Battles, the GTS, and Wonder Trades.

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Source: http://www.pokemon-gl.com/oras/close_announcement/en/