Seasonal Ranked Update
Today’s update reworks the Ranked matchmaking system, as our inaugural six-month Ranked Season is ready to begin. Entering the season, all players will be able to earn a new Rank Medal on their profile that represents their highest performance level for the current season. A Seasonal Rank Medal never decreases in rank once you’ve achieved it. Initial calibration games will be seeded roughly based on your previous skill.
There are seven levels of Rank Medals, and within each level are five stars of progress to earn towards the next Medal. These Medals are: Herald, Guardian, Crusader, Archon, Legend, Ancient, and Divine.
Your performance in both Party and Solo games is considered when evaluating your skill and determining when your Medal gets upgraded, with Solo games having a bigger impact. In order for players to achieve either the Ancient or Divine Medals, only Solo-game performance is considered.
This update also expands the Leaderboard system to include many more players. Players with 5 stars on the Divine Rank Medal (the highest rank) will now have a leaderboard number listed with the medal that broadcasts their position amongst other players. This leaderboard position will always be displayed alongside the Medal, and will be visible to all players in the game and on your profile.
Source: Dota 2 Blog