How to: Upgrading plugins
By default, plugins will be upgraded if they haven't been upgraded manually and if the version from the docker image is newer than the version in the container.
Versions installed by the docker image are tracked through a marker file.

To force upgrades of plugins that have been manually upgraded, run the docker image with `-e PLUGINS_FORCE_UPGRADE=true`.

The default behaviour when upgrading from a docker image that didn't write marker files is to leave existing plugins in place.
If you want to upgrade existing plugins without marker you may run the docker image with `-e TRY_UPGRADE_IF_NO_MARKER=true`.
Then plugins will be upgraded if the version provided by the docker image is newer.