According to the Pokemon GO Team, players can expect "the biggest update to Pokémon GO" to roll out over the coming weeks. The massive update is planned to include an overhaul of the gym battling system in addition to new features like raid battles.
https://www.notebookcheck.net/Pokemon-GO-to-receive-a-massive-overhaul-of-its-gym-battling-system.229238.0.html