The API exposed in this project (setClusterParameter, getClusterParameter, _configSetClusterParameter) will be gated behind FCV 6.0. Therefore, all future cluster parameters will be gated behind FCV >= 6.0. When downgrading below 6.0 by running setFeatureCompatibilityVersion, a hook should drop the config.clusterParameters collection on the config server and all shards.

1. Add a hook to the implementation of the setFeatureCompatibilityVersion command that deletes all cluster parameter documents from config.clusterParameters on the config and shard servers.