To upgrade from Oracle 11gR2 to Oracle 18c/19c, we need to remove Streams setup. For detailed steps, refer to the section “Removing an Oracle Streams Configuration” in the Oracle Streams Concepts and Administration Guide specific for the Oracle release from which you are removing. It is observed that even though there are no Streams Processes or Rules.
connect / as sysdba
delete from sys.apply$_source_obj ;
delete from sys.apply$_source_schema;