Add a "server_used" parameter in the report which behaves like "master_used"
Bump the report version.
Update the report schema and docs.
Maybe delete "master_used" in puppet 7 (and bump report version again) as a separate ticket?
Merged to master in https://github.com/puppetlabs/puppet/commit/28e5d60e80bbcbec3924c2bec570d9fdcb448c10