As part of your upgrade plan , review the desupported features in this Oracle Database release.

• Desupport of Oracle Data Provider for .NET Promotable Transaction Setting
  The Oracle Data Provider for .NET PromotableTransaction setting is desupported because it is no longer necessary. All compatible database server versions support transaction promotion.
• Desupport of Oracle Multimedia
  Oracle Multimedia is desupported in Oracle Database 19c, and the implementation is removed.
• Desupport of the CONTINUOUS_MINE feature of LogMiner
  The continuous_mine option for the dbms_logmnr.start_logmnr package is desupported in Oracle Database 19c, and is no longer available.
• Desupport of Extended Datatype Support (EDS)
  The Extended Datatype Support (EDS) feature is desupported in Oracle Database 19c. All Data types that the EDS feature supported are now supported natively by both Logical Standby and Oracle GoldenGate.
• Data Guard Broker MaxConnections Property Desupported
  Starting in Oracle Database 19c, the Oracle Data Guard broker MAX_CONNECTIONS attribute is desupported.
• Desupport of Leaf Nodes in Flex Cluster Architecture
  Leaf nodes are no longer supported in the Flex Cluster Architecture in Oracle Grid Infrastructure 19c.
• Desupport of Oracle Streams
  Starting in Oracle Database 19c (19.1), Oracle Streams is desupported. Oracle GoldenGate is the replication solution for Oracle Database.
• Desupport of PRODUCT_USER_PROFILE Table
  Starting in Oracle Database 19c, the SQL*Plus table PRODUCT_USER_PROFILE (PUP table) is desupported.