Source: https://twitter.com/PokemonGoApp/status/753843221491355648
Lock if old
p.s: I advice people to stop following rumors because so far there is 0 leak about which country will be next.
EDIT: here some details about futur releases
Source: http://nintendoeverything.com/niantic-ceo-wants-pokemon-go-in-200-markets-some-pose-difficulties/John Hanke, CEO of Niantic (co-developer of Pokémon GO), has stated that he wants Pokémon GO to be out in about 200 different regions. He also noted that the company’s other, similar game Ingress took about two months to reach that point, but he declined to comment on a timeframe for Pokémon GO’s releases. According to Hanke, the company is also currently working on strengthening the servers to deal with the current popularity and any future rollout.
Hanke also made note of two regions that could face release difficulties: South Korea and China. In the case of South Korea, the country has limits on Google’s mapping functionality, due to security concerns with North Korea. However, Hanke stated that “there are solutions to that.” As for China, the country has many regulations that Niantic would have deal with.