Valve released the new ranked seasons. All players must play 10 games to recalibrate. A first MMR distribution by medal is available using players’ data.
Announced about 20 days ago, the new seasonal ranked system has finally reached the main client. The old MMR is gone and after 10 calibration games you will receive a new shiny medal.
Here is all the info provided by Valve:
The rank medal represents your best performance level during a season.
The seasonal medal never decreases in rank once achieved.
The initial calibration games will be based on your previous skill.
Only after playing 10 games you will know the new placement.
Both your solo and party games are considered when evaluating your skill, but solo games have a bigger impact.
There are a total of seven ranks, and each one is composed of five stars to mark your progress towards the next medal. The Ancient and the Divine medals are achievable only through solo-play.
The new ranks: Herald, Guardian, Crusader, Archon, Legend, Ancient, and Divine.
December 5 update - All medals have been redesigned
Valve also expanded the leaderboard system to include more players.
Old vs new MMR and Distribution by medal
Reddit user clarinetEX - who kindly allowed us to use his data - shared a google form asking players their old and new solo/party MMR, the new medal, stars, number of victories during the calibration games, and more.
Using the data from the survey, u/mmrisjustamedal presented a first rough MMR distribution by medal:
Herald: 0 - 839 MMR
Guardian: 840 - 1679 MMR
Crusader: 1680 - 2519 MMR
Archon: 2520 - 3359 MMR
Legend: 3360 - 4199 MMR
Ancient: 4200 - 5039 MMR
Divine: 5040 - 5740+ MMR
ClarinetEX also shared the following graph highlighting the shift from the old system to the new one.
The average MMR decreased and the reduction is proportional to your old one. The higher it was, the more deflation you will experience. For example, Evil Geniuses’ Syed Sumail "SumaiL" Hassan went from 8.3k to 6.7k MMR.
Please note: This isn’t an official distribution released by Valve, but just a first very rough estimate based on the data the users shared. We don’t know the trustworthiness of this graph, but it is helpful to have an idea of the changes.
Update: Monthly Rank Distribution
Starting from February 2018, I will release a Seasonal Rank distribution updated monthly. In the article you can also find the latest data on the estimated MMR by medal which is (imho) percentile based.