Oracle Database 19c is the Long Term Release for the Oracle Database 12c and 18c family of products. It’s available on all popular on-prem platforms, Oracle Exadata and Oracle Database Appliance, and in the Oracle Cloud. As the latest Long Term Release, it offers customers the highest levels of stability and the longest error correction window. And, by upgrading to Oracle Database 19c customers can have Premier Support and Extended Support through to April, 2024 and April 2027 respectively (see blog post for more information). Therefore in the interests of maintaining business continuity, customers still running on prior releases (e.g. 11gR2, 12cR1, 12cR2, 18c) are encouraged to start planning their 19c upgrades before current support windows expire. BTW, always refer to MOS note #742060.1 for the latest status of Oracle Database releases and support coverage.
Upgrading is also an opportunity to take advantage of both technology innovations and recent licensing changes. At no additional cost, customers can (for example):
Also note that Standard Edition High Availability provides cluster-based failover for single-instance 19c SE2 databases.
As depicted above, there is a direct upgrade path to Oracle Database 19c from 11gR2, 12cR1, 12cR2 and 18c releases. And, for some excellent advice on planning and executing your upgrades, take the time to tune into the Oracle Database 19c Upgrade 'virtual classroom' webcast series (registration required).
Finally, always refer to the Oracle Database 19c Upgrade Guide before upgrading!