I read that there's a trick where you rename your Eevee to Rainer and it will evolve into Vaporeon (and likewise, other names will result in other evolutions), but it's not working for me.
What are the possibilities of the things I'm doing wrong? Do I still have to have 25 candies to evolve it?
Yes, you still need to feed your Eevee candies to evolve it. The trick you're referring to is a popular trick to control which Pokémon Eevee will evolve into.
In the traditional games, you need to give Eevee an evolution stone to make it evolve. A Water Stone for Vaporeon, a Thunder Stone for Jolteon, and a Fire Stone for Flareon. Since these stones don't exist in Pokémon Go, Eevee evolves randomly into either.
To avoid having to rely on luck, people have attempted to determine what Eevee will evolve into. Eventually, it was discovered that renaming Eevee allows players to define which Pokémon Eevee will evolve into, assuming that evolution had not been registered in their Pokédex before:
| Evolution | Eevee Nickname | Regular Evolution method |
|---|---|---|
| Vaporeon | Rainer | Chosen at random if no other evolution requirement is met |
| Jolteon | Sparky | Chosen at random if no other evolution requirement is met |
| Flareon | Pyro | Chosen at random if no other evolution requirement is met |
| Espeon | Sakura | Walk 10km with Eevee as your Buddy, and evolve in the day |
| Umbreon | Tamao | Walk 10km with Eevee as your Buddy, and evolve at night |
| Leafeon | Linnea | Evolve near Pokéstop under the effect of Mossy Lure |
| Glaceon | Rea | Evolve near Pokéstop under the effect of Glacial Lure |
| Sylveon | Kira | Earn 70 Hearts as your buddy |
Restarting the game is only used to ensure that your Eevee has been renamed, since the servers aren't always available. By restarting, you can determine if your Eevee has been successfully renamed before you spend candies to evolve it.
Of course, this doesn't change the fact that you still need candies to evolve your Pokémon. Also keep in mind that the trick only works once per nickname (thanks @MBorg).
in the pokedex it says the the environment in which the eevee lives will affect the way it evolves, but changing where you evolve your eevee will not make a difference. After the update many of my friends and I have been getting almost exclusively Jolteons. Maybe because we have a lot of vaporeons. Renaming your Pokemon Rainer over and over again used to result in a lot of vaporeons, but now it only works once. Jolteons are more common because when you evolve them the cp multiplier is lower, so you can evolve 3 CP 650+ eevees and have three 1300 jolteons :( whole if you'd gotten vaporeons the CPs would have been higher.
