>>46586684They explicitly state in DP that Infernape forgot Flame Wheel when it learned Flare Blitz, and whenever Pokemon learn a new move when they already know four, they stop using one of the old moves.
They bring this up again in SM as when Kiawe's sister says that Ash should have his Pikachu use Catastropika too, but Rotom Dex mentions that Pikachu needs to know Volt Tackle in order to be able to use it, which is a move Pikachu doesn't know anymore since it forgot it when it learned Electro Ball (and then Electro Ball upgraded itself into Electroweb)
So yes, it's now canon to the anime that Pokemon can know only know four moves and forget an old one or the old move "evolves" into the new ones
