I don’t see a way unless you have a pre-upgrade copy of the package, but here are some indirect ways -
Namespace - Can you navigate to the folder namespace in the backend and see the timestamp on the internal file for the connection?
DB Logs - This message usually happens when the Listener is stopped on the DB side (or incorrect SID, which seems unlikely in your case). You can look for a timestamp in the DB logs to see if this Listener was stopped any time recently.
Connection History - Else if the DB is online, you can get the DBA to check when was the last time the user configured in this connection, actually connected to the DB.
KM
#DB#webMethods#Integration-Server-and-ESB#adapter#webMethods-io-Integration