Since two versions of WSL exist, it is possible to up and downgrade.
You can downgrade single images from WSL2 to WSL1 and vice-verse.
To see what WSL versions your images have:
C:\Users\jonasbn>wsl -l -v
NAME STATE VERSION
* Ubuntu-18.04 Running 2
docker-desktop Running 2
docker-desktop-data Running 2
kali-linux Stopped 2
You can set the WSL version for an image:
C:\Users\jonasbn>wsl --set-version kali-linux 1
Conversion in progress, this may take a few minutes...
C:\Users\jonasbn>wsl -l -v
NAME STATE VERSION
* Ubuntu-18.04 Running 2
docker-desktop Running 2
docker-desktop-data Running 2
kali-linux Stopped 2
And when you list afterwards, you can observe that the version of the WSL for the image has changed.
C:\Users\jonasbn>wsl -l -v
NAME STATE VERSION
* Ubuntu-18.04 Running 2
docker-desktop Running 2
docker-desktop-data Running 2
kali-linux Stopped 1