Patches to apply before upgrading Oracle GI and DB to 19c or downgrading to previous release
Oracle 19c | Applying Patch – Duh! Microsoft did it again
Important Recommended Patches for Oracle Database 19c
Deploying Oracle 19c RAC with Red Hat Enterprise Linux 8.2 on vSphere 7 | Design Guide—Oracle RAC Database on PowerStore T Storage | Dell Technologies Info Hub
Download and install Oracle Critical Patch Updates (CPU) for Symantec DLP