With the KeyHelp update to version 20.3 a new firewall management was introduced. The (old) firewall management used until then was considered deprecated since then.
With the upcoming KeyHelp update, this outdated firewall management will now be removed from the KeyHelp management interface.
If you have not yet switched to the new firewall management, your configured firewall rules will remain active after the update, but changes will have to be made via the new firewall management in the future.
This change only affects servers running Debian 9 / Ubuntu 16 / Ubuntu 18 operating systems that have not yet migrated to the new firewall management.