There is currently no manual from developer Niantic on how to control Eevee's evolution in the "Pokémon GO" game in order to achieve Flareon, Jolteon and Vaporeon. Many players have tried and tested every theory they can come up with, and after many failures, they have come up with a way to control the evolution.

Game Rant reported that players found out that instead of having a random evolution, one needs to use different names from the original anime, Pyro, Sparky and Rainer, also known as the Eevee brothers.

"Pokémon GO" players need to rename first their Eevee character. Inside the game, open the menu, select the Eevee character that needs to evolve and change its nickname. Players need to choose the character with the highest CP and be sure to rename it properly. They have to save the changes then restart the game.

• Sparky = Jolteon
• Rainer = Vaporeon
• Pyro = Flareon

After the game restarts, the only option now is to evolve, and based on the publication's own account, they were able to achieve a 100 percent success rate in every evolution. This has also been proven to be successful by many "Pokémon GO" players on Reddit.

Meanwhile, it is believed that a "Pokémon GO" Gen 2 will soon be released by Niantic, where Eevee is said to have two more types of evolution, Espeon and Umbreon.

It is said that time is a major factor in achieving the desired evolved state of Eevee. Espeon will require a high rate of happiness during the day, while Umbreon can be achieved when there is a complete trust in the trainers at night.

"Pokémon GO" is currently available for Android and iOS, while the Gen 2 is expected to be available by early next year.