Platform -> Upsun config docs

[koko236]

I've been using platform.sh for about 7 years now I'm trying to setup first project after rebranding to upsun.

1. I've created .upsun/config.yaml but when pushing to server using Platform CLI 5.6.0 I get message about missing ./platform directory in my project. I also instaled upsun 5.6.0 but it doesn't recognize current folder as a project - when running commands in project folder it asks me to select a project.
2. I created whole old style platform config and I'm able to deploy the app with some runtime errors. The problem is docs for platform config seem to be gone, and upsun config is not picked up by the deployment.

I have 2 questions is as follows:

1. How do I make the new config work with platform CLI or upsun CLI?
2. And/or where are platform config docs now?

On the whole I must say that my initial experience with the project configuration after rebranding is not very smooth which I think might be partly due to the docs trying to appear as if there never was platform.sh in the first place. Is there any link where the migration process is explained in detail?

[koko236]

Ok, it might be that I was reading Upsun Flex docs (which talk about .upsun/config.yaml) and I should be reading Upsun Fixed docs (which sort of talk about old config)? But still:

This is displayed in console (note config.yaml in root):

This in the Upsun Fixed docs (note traditional .platform.app.yaml):

Could anyone explain what is the relationship between Platfom / Upsun, Fixed / Flex, and config formatting?