The function of the catupgrd.sql script is replaced by the Parallel Upgrade Utility, catctl.pl, and the dbupgrade and dbupgrade.cmd scripts.
In earlier releases of Oracle Database, the catupgrd.sql Upgrade Utility processed the upgrade. Starting with Oracle Database 12c release 1 (12.1), this script is replaced by the catctl.pl Parallel Upgrade Utility, and its command-line script, dbupgrade. The Parallel Upgrade Utility provides both parallel processing mode and serial modes.
The dbupgrade script calls catctl.pl to create and alter a set of data dictionary tables. The upgrade scripts also call catctl.pl to upgrade or install the following database components in the new Oracle Database 12c database:
Oracle Database Catalog Views
Oracle Database Packages and Types
JServer JAVA Virtual Machine
Oracle Database Java Packages
Oracle XDK
Oracle Real Application Clusters
Oracle Workspace Manager
Oracle Multimedia
Oracle XML Database
OLAP Analytic Workspace
Oracle OLAP API
Oracle Text
Oracle Spatial and Graph
Oracle Data Mining
Oracle Label Security
Messaging Gateway
Oracle Database Vault