Infamous Innovator/ROM researcher @SciresM tweeted earlier this evening revealing new information he discovered about the up-coming update to Pokémon Bank and Poké Transporter.
In his next few tweets (by now SciresM had shared the news on Project Pokémon IRC too), he confirmed support for newly released: Pokémon Ultra Sun and Ultra Moon and Pokémon Gold and Silver, which were released back in September for the Nintendo 3DS Virtual Console. As a welcomed bonus, it appears that Poké Transporter was updated to add support for [unreleased] Pokémon Crystal on the Nintendo 3DS Virtual Console.
One more thing was brought up by SciresM in Project Pokémon's main IRC channel (#projectpokemon); the event-only Pokémon, Zeraora, was referenced in the text dumps for this update! No word yet on an official date for that event Zeraora.
At the time of writing this, the official Pokémon Bank website has only updated their Pokémon Bank + Poké Transporter "map" (shown above) and current details for the services are still in need of an update. It reads as follows:
With the latest Pokémon Bank update, the Pokémon that adventured with you in the following games will be able to join you in Pokémon Sun and Pokémon Moon:
* Pokémon Omega Ruby
* Pokémon Alpha Sapphire
* Pokémon X
* Pokémon Y
* Pokémon Black Version
* Pokémon White Version
* Pokémon Black Version 2
* Pokémon White Version 2
* Pokémon Red (Virtual Console)
* Pokémon Blue (Virtual Console)
* Pokémon Yellow: Special Pikachu Edition (Virtual Console)
On the other hand, Nintendo's 3DS support page (Japanese) shows official announcements for Pokémon Bank and Poké Transporter v1.4, sans mention of Pokémon Crystal.
In-Game Images (Spoiler)
With Pokémon Bank being updated to version 1.4, some of you might be wondering if we will receive the Mewnium Z like we did when Pokémon Bank version 1.3 was released. No, but it's surprising easy to claim it in USUM.
After you make it to Heahea City on Akala Island, head to the Tide Song Hotel. Enter to the lobby, then go to the elevator to the left of the check-in desk; select 3F. After you land on the third floor, head left (your player's right) around the corner and enter the first door you see. Talk to the jewelry shop owner while Mew is in your party. He will eventually give you the Mewnium Z Z-Crystal. You can repeat these steps with Marshadow and Snorlax in your party to receive Marshadium Z and Snorlium Z respectively.
SciresM's Twitter; Nintendo.co.jp; Pokemonbank.com; Pokemon.com