This update includes a long waited new functionallity: Templates
With templates you can define your own custom prefixes players can choose between (based on permissions of course).

New Templates functionallity
Added new permissions
Added new config options and messages
Folia support
Fixed PrefiX PAPI version
Improved command handling

For this update there are new messages and config options available. Best practice is to delete your old ones and let them regenerate OR take the new keys from the documentation: Config and Language.
Deleting is no langer required with the 7.01 update.