while reading the 12c upgrade guide I noticed that the catupgrd.sql is deprecated:
“Oracle Database 12c introduces the new Parallel Upgrade Utility, catctl.pl. This utility replaces the catupgrd.sql script that was used in earlier releases. Although you can still use the catupgrd.sql script, it is deprecated starting with Oracle Database 12c and will be removed in future releases. Oracle recommends database upgrades be performed with the new Parallel Upgrade Utility, catctl.pl.”
so prepare for changing your upgrade process …
Daniel Westermann's Blog 