In Niantics newest announcement for September, Tier 2 and Tier 4 raids will be removed from Pokemon Go. For those who expressed concern about the placement of the Pokemon in these tiers, Niantic also verified that they would be either moving up or down depending on the Pokemon. Along with this movement of Pokemon, the rewards for each raid battle is also subject to change, but nothing has explicitly been said about this just yet. As this announcement came with a bigger list of things that are being changed in the game, Niantic Support also says that they will be releasing more detailed updates about these mechanics soon.
At the same time as this news, Niantic also revealed that they will be adding Mega Evolutions to the mobile game. This update is coming on August 28th and will take players physically updating their game.
As Pokemon Go adds Mega Evolution, there is also a new addition of a resource called “Mega Energy”(which can be collected by Mega Raid). Mega Energy can be gained by defeating Mega-Evolved Pokemon in Raids (the higher the level, the more Mega Energy gained). As of now though, the only Mega-Evolved Pokemon Venusaur, Charizard, Blastoise, and Beedrill.
There is a catch with this new addition of Mega Evolutions, however. Players are only allowed to have one Mega-Evolved Pokemon in their party at a time. If a player chooses to Mega Evolve a new Pokemon, the current Pokemon with a Mega Evolution will revert back to its non-Mega Evolved form (but can be re-evolved for a smaller amount of energy). Along with this, Mega-Evolved Pokemon can battle in gyms, but they are not allowed to defend them. They are also not allowed to participate in the Battle League.