Starting from Season 4, the graph and percentile tables in this article will show the rank data split between Core and Support MMR.

From Season 3 to Season 4

The average rank dropped from Archon 4 to Archon 1.

The 70 percentile moved down from Legend 3 to Archon 5.

The percentage of players ranked at Ancient and above diminished from 15 to 11%.

Season 4 matchmaking update

Valve completely overhauled the Dota 2 matchmaking system in Season 4 with a gigantic update in September, and improved it with more drastic changes on October 10th.

Their work is not concluded because - while the new system is working well for the majority of the players - there are still big flaws, especially at the highest ranks. I am certain they will continue gathering data and improve it in the months to come.

October 11th: We are aware of matchmaking queue times taking a very long time and are working on improving it. We may need to slightly relax a few of the new quality settings for the weekend and then we’ll continue tightening things on Monday.

Below, a quick summary of the current situation after the matchmaking updates released so far.

Party matchmaking

Five-player parties are now matched only against other five-player parties.

Solo players will be matched against other solo players or at most against one party of two.

The acceptable MMR spread within a party has been reduced from 2800 to 2000 in order to improve the match quality of both teams.

Party at high MMR

For any party that includes an Immortal player, every player in that party will be considered the same rank as the highest player in that party.

This new rule is necessary to counter the high frequency of matchmaking abuses at high ranks, but on the other hand it will also affect “regular” parties with large MMR disparities, which might impact the match quality.

October 18th: Immortal players will only ever be matched with other Immortal or Divine players in Ranked. For example, that if there is a Divine player in a party with players below Divine, that Divine player will as a result never end up in a match with other Immortal players.

Role symmetry

Misaligned roles have a meaningful impact on game quality. An example of this is when the mid player for one team has the highest rank on their team, and the mid player on the other team has the lowest rank. This tended to cause games to be really volatile and not enjoyable.

It is not fun when a core player is able to stomp your whole team, so starting from this season there will be rank symmetry between players on the same role.

Also, the matchmaker will try to avoid having supports as the highest MMR players in a game, whenever possible.

Bans and punishment

Players that have a behavior score below 3000 are no longer able to use chat or voice until their score rises above the acceptable threshold.

Booster and exploiter detection algorithms are constantly updated, and there will be regular ban waves. Lots of users have been banned for violating the Steam Service Agreement that prevents the purchase or sale of Steam accounts, and others because they reached an extraordinarily low behaviour score.

You can now report players who do not play the role they queued for.

Valve is really trying their best to fight matchmaking abuses, in fact even pro players are punished. In the video below, the famous Jacky “EternaLEnVy” Mao got banned for six months, most probably due to a combination of role stealing and low behaviour score.