Strapi Migration / Update V3 -> V4

Anyone already migrated a Strapi V3 Installation to V4?
The Migration Guide says “coming soon”.

I would like to add new features to a project, but would like to have v4 on it first. So it’s holding me kind of back.

It’s still coming soon.
No guides released yet.

Yes, I assume that this will happen at some point. But my question was rather if someone has already done it without a guide?