Ferrari is coming with a brand new engine. Surely they'll also be allowed to 'update' the engine once mid-season.
Hell, Honda announced they'll make another fresh engine for 2022. No way that this 1 change per season means they can't introduce a new or updated engine in winter time.
The season is not started yet, they can do and come up whatever they want, as long as it's homologated.
What this IMO means, is that if you start the 2021 with a 2020 engine that is updated, and you then midseason replace it with a totally new spec engine,
then this engine does NOT allow to be updated anymore, since essentially, that new engine IS the update.
so either you keep your 2020 engine, update it in the winter, and then when the season kicks off in bahrain you can only update it once during the season, that's it.
OR, you go with a new, untested spec '2021' engine into the season, and then also only have it updated during the season.
the decision here has to do with risks.
option 1 ) a completely new engine might come at a few unexpected surprises, which 1 update will not fix.
option 2 ) using your known '20 engine might cost you some potential power compared to a new format, BUT has a more trustworthy base to work with and 1 update should be enough.
i think the compromise is what to do with 2022 over 2021.
If you introduce your eyed 2022 engine in 2021, you'll lose some in the 21 season, but gain knowledge and solid base which you can work on untill the start for the 2022 season.
if you keep your '20 engine in '21, you get a more reliable 2021 season, but will start fresh and 'more risky' when the 2022 season kicks off.
There are loopholes here clearly, and i'm sure these will be exploited: B-teams.
You keep your A-teams scot free,
and go with the B-team to take the 'development platform' route.
Both Mercedes, Ferrari and Honda have these options: Haas, Williams and AlphaTauri are their 'development platforms'.
Surely this is why Ferrari has increased their relationship with Haas (and probably dropped AlfaSauber since they perhaps said NO), and Merc with Williams.
Meanwhile, Renault is now in the 'cold' with Alpine.
both Mclaren and Aston Martin have the benefit of Mercedes' deal with Williams: Williams will be the test mule, and both AMG, AMR and MCL can get the benefit both in 2021 aswell as in 2022 from that project.
Let's put it like this: Merc, Aston and Mclaren start the season with a winter-updated 2020 spec engine which will grant them reliability.
Williams will be 'forced' to race with the 2021 spec engine, which will come with unknown variables. They'll be pushed to push that engine to the test in order to gather important data.
IF the 2021 engine is better, perhaps with what they expect from an update, in all expected areas compared to an updated 2020 engine, then Merc, Aston and Mclaren will probably go with that updated 2021 engine. as their '1 token'.
this is how i read the rules, however i might be miles and miles off.
"Explain the ending to F1 in football terms"
"Hamilton was beating Verstappen 7-0, then the ref decided F%$& rules, next goal wins
while also sending off 4 Hamilton players to make it more interesting"