Here are the steps I did to upgrade the docker container of Unifi Controller (https://github.com/jacobalberty/unifi-docker/) on my Synology.
- Make a backup of the Unifi controller
- Open the Docker application
- Go to the Registry, and search for the image.
- Click download, and choose the ‘latest’ tag
- This will download the latest image and overwrite the existing older image
- Stop the container that was built on the old image.
- Highlight it and select the Clear action.
- Restart the container and it will be built from the new image.