Stats
Movesets
Generation 1 movesets have been rebalanced. Some moves like Hyper Beam got their damage upped from 120 to 150. Dragon Claw became a 3-bar move. Some quick moves like Dragon Breath or Water Gun are much slower than before. Dragon Breath is only a little bit faster than Steel Wing now (retroactive change).
Also, all moves are 1,2 or 3 bar now, there isn’t 4 or 5 bar moves anymore. the dreaded Twister is now a 3-bar move (retroactive change).
More details will be revealed by the GAME_MASTER.
Newly caught Gen 1 pokemon can have new moves too, like Iron Tail on Dratini. Evolving an already owned Gen 1 Pokemon can also result in a new moveset, like getting a Dragon Rage/Outrage Gyarados from your old Magikarp.
Note: don’t transfer any Gen 1 Pokemon until we know for sure whether they can still get all the former movesets or if some movesets have become legacy movesets.
COMBAT POWER
Lapras Has been nerfed. We knew that Lapras had been left untouched by the end of november stat rebalance and that the new conversion formula was supposed to nerf him. He unfortunately got this overdue change.
Other pokemon CP seem untouched.
Spawns
Nests
It rather seem that some nests were disabled, other became Gen 2 pokemon nests, some turned into Gen 1 pokemon nests, so it’s more a standard nest migration.
There was also a spawn point reshuffle (location/time), as it usually happens when Niantic touches nests.
Ditto
Ditto has been reported to come out of some gen 2 pokemon. Hoothoot and Sentret seem confirmed so far.
https://www.reddit.com/r/TheSilphRoad/comments/5uilwd/my_first_hoothoot_was_a_ditto_what_other_new/
Togetic, Togepi, babies
Togetic confirmed to spawn in the wild. Babies are also out there.
Catch
New catch bonus
You get a 50XP bonus if you catch a Pokemon in only one throw. Completely missing the Pokemon with your first ball still counts as a throw, so no bonus in that case.
Critical catch
Critical catches have been implemented.
New Pokemon movement on catch screen
Pokemon move in new ways during the catch sequence. Ledyba will move in a “V” motion, while Qwilfish will move sideways from left to right, with their catch circles following them. Other users in this same thread also report new movements for gen 1 pokemon like Venonat or Abra.
Berries
You can only use 1 berry at a time on a pokemon. So no, you can’t use a razz + a nanab on a pokemon.
Candies/Evolutions
Candies
You can now get 5 candies when catching a Stage 1 evolution. 10 candies for a stage 2 evolution. Hitmonchan/Hitmonlee candies have been unified into Tyorgue candies.
Evolution items
Evolution items are required for some evolutions such as Scyther->Scyzor (Metal coat). Evolution items come out of pokestops and are consumed once used. For pokemon with branched evolutions such as Slowpoke or Gloom, you get 2 evolution buttons, allowing you to choose with one you want. Eevees only have one button.
Other changes
Medals
The Johto medal and Delinquent medal (Dark type) have been added.
Regionals
No exclusive regional confirmed yet.
Eggs
Gen 2 pokemon have been added to the egg pool.
Level up bonuses
X15 Nanab berries at level 31, X20 Nanab Berry at level 35. Probably changed for all levels.
Fainted pokemon
Fainted pokemon have all been revived.
Buyable items
As expected with the new avatar customization options implemented, you can now buy additional clothes in the shop.