FTP messages and replies are contained in two z/OS® UNIX message catalogs as follows:
Contains messages that the FTP daemon, server, and client issue.
Contains replies that the server sends to the client.
If messages in either of these catalogs need to be modified, the timestamp that is contained in the shipped level of the FTP catalog must be preserved in the modified catalog.
This timestamp is included within and is unique to each catalog. When FTP (client or daemon) is started, FTP verifies that this timestamp matches the timestamp that it expects. This prevents FTP from presenting the wrong message when the z/OS UNIX message catalogs and FTP are not synchronized.
When you apply a service update to FTP load modules that requires a service update to a catalog, you must install both at the same time. Otherwise, FTP will report an error and use default messages instead of messages from the catalog.
If you are using a modified FTP catalog, the catalog that matches the service level of FTP load modules needs to be updated with your local modifications, and the timestamp of the catalog must be preserved.