11/15/2025 - Fix

So, the current version of Docker depreciates the version of the API used by Portainer.  This can be fixed a couple of ways.  One is to downgrade the version of Portainer to 2.20.2 but this didn't work too well for me.  The other method is to lower the minimum required API to 1.24.  It's not ideal either, since it could cause problems later on.  The final choice is to wait for Portainer to release an update that fixes it.

Here are the steps for lowering the API minimum to 1.24:

1. sudo systemctl edit docker.service
2. Add this part above the line ### Lines below this comment will be discarded:

   [Service]
   Environment=DOCKER_MIN_API_VERSION=1.24

3. Save the file and exit (Ctrl+O; Ctrl+X in Nano, the default for Linux Mint)
   
4. sudo systemctl restart docker

To revert the change, repeat all steps but, instead of adding those two lines, delete them.

Do Not Recommend How to downgrade to 2.20.2:

docker run -d -p 8000:8000 -p 9443:9443 -p 9000:9000 \
  --name portainer \
  --restart=always \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -v portainer_data:/data \
  portainer/portainer-ce:2.20.2

To update to the current version, replace "2.20.2" at the end with "latest" and run it again.