Premier Support for Oracle 12cR2 is slated to end by Nov 2020 and there does not appear to be any intention by Oracle to provide Extended Support beyond this time frame.
Planning to upgrade to Oracle 19c. When does 14.3 plan on supporting Oracle 19c.
Release: 14.2
Release: 14.3
Component : CA IDENTITY SUITE (VIRTUAL APPLIANCE)
Oracle 19c is currently supported for both versions 14.2 and 14.3 of the Identity Suite.
Please see the documentation for the Certification Matrix and for Oracle 19c specific requirements in the documentation, for example for Identity Portal 14.3:
https://techdocs.broadcom.com/content/broadcom/techdocs/us/en/ca-enterprise-software/layer7-identity-and-access-management/identity-portal/14-3/platform-support.html
Please review the installation instructions carefully for Oracle 19c specific steps. For example, when installing Identity Portal against Oracle 19c you will need to download and install a small hotfix during the installation to properly support Oracle 19c as described in the Portal installation guide, for example for JBoss:
https://techdocs.broadcom.com/us/en/symantec-security-software/identity-security/identity-portal/14-3/installing/installing-ca-identity-portal/ca-identity-portal-installation/installing-ca-identity-portal-on-jboss.html