The Pokémon Global Link website has announced the details of Season 13 for Rating Battles. The Special format for this season will be Double Battles, with only Legendary and Mythical Pokémon and Ultra Beasts allowed.

Powerful Pokémon Clash in Rating Battle Season 13

Rating Battle Season 13 is coming, and you’ll be able to put your battling skills to the ultimate test as you compete with other Trainers from around the world. The Rating Battle leaderboards reset each Rating Battle Season, so everyone starts on equal footing. As you battle, you’ll move up and down the rankings based on your match outcomes. Rating Battle Season 13 runs from November 6, 2018, at 00:00 UTC, so get in there and start battling!

Rating Battles are available in Pokémon Ultra Sun, Pokémon Ultra Moon, Pokémon Sun, and Pokémon Moon, but please note that Pokémon Ultra Sun and Pokémon Ultra Moon battles will be ranked separately from Pokémon Sun and Pokémon Moon battles. Also, Pokémon and moves introduced in Pokémon Ultra Sun and Pokémon Ultra Moon may not be used in Pokémon Sun and Pokémon Moon Rating Battles.

The Special format for this season will be Double Battles, with only Legendary and Mythical Pokémon and Ultra Beasts allowed. Pokémon brought in from previous games via Poké Transporter will be permitted. With so many famously powerful Pokémon eligible for these battles, expect some very challenging matchups!

Source: https://3ds.pokemon-gl.com/information/38d5a921-a2e3-4183-a1f1-42e0b5900972