To stop all the „why is my mmr so low“ posts and questions

There are many widespread false claims about what happens with the MMR on season changes within an expansion, so please let me explain.

MMR does not get resetted during an expansion!

Most parts of the injected MMR (which causes the inflation) is subtracted from the last MMR you had for the new season. It has been like that for years now.

This means if you stopped playing on 2.8k mmr and the injected MMR accumulated to 500, you will now have the MMR of roughly ~2.4k.

That being said, I have no idea how much mmr was injected this season. It should be fairly easy to find out rough numbers, but I do know that it started fairly late into the season (in comparison to past seasons) but the injection itself was fairly big.

So you should be able to see a significant decrease of your MMR, but definitely no reset!