HuskSync 3.8.5 adds support for Minecraft 1.21.6 and fixes bugs.

• Added support for Minecraft 1.21.6 servers on Paper and Fabric
• Added a debug configuration option to disable check-in petitions (not recommended unless you know what you are doing)
• Fixed a bug on Paper servers where persisted locked maps not syncing correctly after a server restart occurs (#498)
  • There's still an issue affecting locked maps in item frames I plan on fixing soon.

To update from 3.8.4, just drag+drop. There are no config changes (unless you happen to want to disable check-in petitions with the new option; not recommended unless you know what you are doing)