Since Pokémon GO launched back in July, players have only been able to capture Pokémon from the first generation of games, but that could be changing soon. A new update is rolling out now, and data miners have already dug in to see what they can find. According to the team at Silph Road, the update contains data referencing the move Transform as well as data referencing every Pokédex number from 152 to 251. Move set data has not yet appeared for the 100 Pokémon of Generation II, but that could easily change with another update. Hopefully we get an official announcement soon!
Source: Silph Road