https://dirtfish.com/rally/wrc/wrc-e...ars-from-2021/

Engine specs will be frozen in April 2021 for five years, meaning the teams cannot develop their engines during that time.

Also it says M-Sport are not bringing new updated parts yet because they have a stock of old-spec parts that need to be used first. The new engine will come in Monte 2021 and new aero maybe in Sardegna. Sad situation for them.