Pokemon GO has added new rosters to their Pokedex adding some Pokemon Gold and Silver to the line up which atleast maybe around 80 pokemons. Johto region pokemons will now be catchable. More than just offering monsters like Chikorita, Cyndaquil and Totodile for capture, the game's latest update refreshes a few other bits as well. You can check the screenshot below for one of the new added pokemon.
For starters, how encounters work is getting a tweak. You'll also have access to new evolution items, two new berries (Nanab slows your quarry while Pinap doubles the amount of candy you'll snag after a successful capture) and some new hats and other clothing for your avatar.
source via official Pokemon Website