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 fixing it:

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

How to downgrade :

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