Downgrade unreal engine 5 project to 4.27 or 4.26

Hello , I’m trying to downgrade my UE5 project to a older version 4.27 or 4.26.

i have done the following.

  1. go to Epic games launcher and clone the project
  2. go to the clone folder and select the project and right click and select ‘‘switch unreal engine version’’ I have done this in 4.26 and 4.27.
  3. the project is opening in the old versions but is missing the map, on the folder i can see the map but not in the editor.

4.i drag and drop the map in the editor but i had the following error ‘’ unknown extension umap’’

I am not sure why it does that , any help is appreciated

Downgrading is not possible.