Review this list of desupported features as part of your upgrade planning.
Starting in Oracle Database 12c release 2 (12.2), the Advanced Replication feature of Oracle Database is desupported.
The Oracle Database Advanced Replication feature is desupported in its entirety. The desupport of this feature includes all functionality associated with this feature: multimaster replication, updateable materialized views, hierarchical materialized views, and deployment templates. Read-only materialized views are still supported with basic replication.
Oracle recommends that you replace your use of Advanced Replication with Oracle GoldenGate.
Placing OCR and Voting Disk files on shared file systems is desupported in favor of placing the files on Oracle ASM.
Starting with Oracle Grid Infrastructure 12c Release 2 (12.2), the placement of Oracle Clusterware files: the Oracle Cluster Registry (OCR), and the Voting Files, directly on a shared file system is desupported in favor of having Oracle Clusterware files managed by Oracle Automatic Storage Management (Oracle ASM). You cannot place Oracle Clusterware files directly on a shared file system. If you need to use a supported shared file system, either a Network File System, or a shared cluster file system instead of native disks devices, then you must create Oracle ASM disks on supported network file systems that you plan to use for hosting Oracle Clusterware files before installing Oracle Grid Infrastructure. You can then use the Oracle ASM disks in an Oracle ASM disk group to manage Oracle Clusterware files.
If your Oracle Database files are stored on a shared file system, then you can continue to use the same for database files, instead of moving them to Oracle ASM storage.
All Oracle JPublisher features are desupported and unavailable in Oracle Database 12c Release 2 (188.8.131.52).
Oracle recommends that you use the following alternatives:
To continue to use Web service callouts, Oracle recommends that you use the Oracle JVM Web Services Callout utility, which is a replacement for the Web Services Callout utility.
To replace other JPublisher automation capabilities, including mapping user-defined SQL types or SQL types, wrapping PL/SQL packages and similar capabilities, Oracle recommends that developers use explicit steps, such as precompiling code with SQLJ precompiler, building Java STRUCT classes, or using other prestructured options.
My Oracle Support Note 1937939.1 for more information about JDeveloper deprecation and desupport
utluppkg.sql scripts are replaced by the Preupgrade Information Tool (
Beginning with Oracle Database 12c release 2 (12.2), the Pre-Upgrade Information Tool scripts
utluppkg.sql are no longer supplied as part of the Oracle Database release. The Pre-Upgrade Information Tool
preupgrade.jar replaces both of these files.
preupgrade.jar Pre-Upgrade Information Tool is supplied with Oracle Database 12c release 2 (12.2). This script has the same capabilities as the scripts it replaces. It can run using the Java Development Kits (JDKs) installed with Oracle Database releases supported for direct upgrade to Oracle Database 12c release 2 (12.2).
Application programming interfaces (APIs) for Transaction Guard listed here are desupported in Oracle Database 12c release 2 (12.2).
The following Oracle Data Provider for .NET application programming interfaces for Transaction Guard are desupported in Oracle Database 12c Release 2 (12.2):
OracleLogicalTransaction.GetOutcome(string, string, string) method
The views listed in this topic are desupported in Oracle Database 12c release 2 (12.2).
Revise any of your SQL statements that use these views.
Starting with Oracle Database 12c release 2 (12.2), Oracle does not support running server-side SQLJ code.
Oracle supports using client-side SQLJ. However, Oracle does not support the use of server-side SQLJ, including running stored procedures, functions, and triggers in the database environment.
Starting in Oracle Database 12c release 2 (12.2), the XML DB features listed here are desupported.
The following features are desupported:
Java classes in package
Oracle XPath function
ora:instanceof. Use XQuery operator
instance of instead.
Oracle XPath function
ora:instanceof-only. Use XML Schema attribute
Function-based indexes on XMLType. Use XMLIndex with a structured component instead.
Oracle XQuery function
ora:view. Use XQuery functions
XML schema annotation (attribute)
XMLIndex index on CLOB portions of hybrid XMLType storage (index on CLOB data that is embedded within object-relational storage)