12.2.3 release comes with both platform and application upgrade options, select correct option while upgrading based on your current version and features being used. You should use only platform upgrade option if already at 12.2.1. or 12.2.2 level.
Also note that Demantra CDP clients should not upgrade to 12.2.3 as CDP isn't supported in 12.2.3 version.
Refer to Oracle's Doc ID 160844.1 for more details around this release.
