WhiteRabbitEXE
Member
I still haven't seen a mewtwo
Outside of the Japanese event they haven't gone live yet, and likely won't until at least September 1st, given that the four birds will be ending on the 31st of this month. They might even wait until the 2nd, given the diary entry in Pokémon Red and Blue that reveals Mewtwo escaped on September 2nd.
Edit: Oops, the diary entry was dated September 1st. So yeah, should definitely happen then.