From Bulbanews, your community Pokémon newspaper.
Pokémon from the National Pokédex will be allowed
The rules for Season 2 of the Rating Battles for Pokémon Sun and Moon have been announced. The Special Battles during this season will be in Single Battles format and run from 17 January until 20 March. Pokémon in the National Pokédex may be used except for Mewtwo, Mew, Lugia, Ho-Oh, Celebi, Kyogre, Groudon, Rayquaza, Jirachi, Deoxys, Dialga, Palkia, Giratina, Phione, Manaphy, Darkrai, Shaymin, Arceus, Victini, Reshiram, Zekrom, Kyurem, Keldeo, Meloetta, Genesect, Xerneas, Yveltal, Zygarde, Diancie, Hoopa, Volcanion, Cosmog, Cosmoem, Solgaleo, Lunala, Necrozma and Magearna. All Pokémon above level 50 will be automatically set to level 50.
The Single and Double battle rules will also be updated in this season to include the same Pokémon as in the Special Battle rules but Ash-Greninja will also be banned in the these two formats. Pokémon that were caught, bred or obtained in Pokémon X, Y, Omega Ruby and Alpha Sapphire and then transferred by Pokémon Bank will also be allowed to be used in the Special, Single and Double Battle formats.
Thanks to Bluesun for the translation.