Pokémon Ultra Sun and Ultra Moon are pretty much the premiere versions of the gen 7 games. They released in November and did get an update a month later. Now, a few more fixes have been made to create a more enjoyable experience.
According to the official Nintendo website, “various fixes to improve gameplay” is the only listing. But thanks to Serebii, we’ve gotten a bit more detail. Changes to some moves have take place such as Ion Deluge, Curse, Power Trick, String Shot and Forest’s Curse. Many of these would cause the game to freeze during competitions.
You must update Ultra Sun and Ultra Moon to version 1.2 in order to access online functions. Get back to the game and keep catching them all on your way to becoming a Pokémon Master.