Battle.net seasons organize division tournaments. Seasons are periodically locked before a new season begins. Players can still move up and down within a division but cannot jump from one league to another, and bonus points will no longer accumulate. However, their "hidden" rating will still be able to change (which affects the AMM and can result in a league jump in the new season). Season milestone rewards will be locked in at this time, and bonus pools will start over. Hidden skill ratings used for matchmaking and league placement will carry over from the previous season. Players will need to play a single placement match in the new season.