The Pokemon Company announced earlier this month that the Pokemon Bank app (for 3DS) would be updated “soon” to provide support for the pair of Ultra releases, and that turnaround was pretty darn quick.
Soon is actually today, and if you have 516 blocks available you can upgrade to version 1.4, which adds said Ultra support, as well as Poke Transporter support for Pokemon Gold and Silver (the recent Virtual Console games).
At this point you have a decision to make if you haven’t finished Ultra yet — on whether or not to bring over your old crew and wipe the floor with the story and postgame. As always it’s your prerogative, but waiting until at least most of the endgame narratives are cased closed is probably going to be the most rewarding. I’m still waiting to move everything en masse, but given that the Marshadow code doesn’t work on either Ultra, I had to at least bring that lowly level 50 over!
Pokemon Ultra Sun and Ultra Moon – Pokemon Bank [Serebii.net]