2309534 - DST problem when upgrading to 12c

You are upgrading your oracle database from source release 10.2.0.5 or 11.2.0.3 or 11.2.0.4 to target release oracle database 12c release1 (12.1.0.2).
In Pre-upgrade phase, when running pre_upgrade_checks.sql, you get errors as below:

***
ERROR: --> New Timezone File in use
Database is using a time zone file newer than version 18.
BEFORE upgrading the database, patch the new
ORACLE_HOME/oracore/zoneinfo/ with a time zone data file of the
same version as the one used in the <source database version> release database.
***

You can run following command to check the currently used TimeZone file version in the source database. You can see the returned version is higher than 18.
SQL> conn / as sysdba
Connected.
SQL> SELECT version FROM v$timezone_file;

New Timezone File, Oracle upgrade, 12C, 12.1.0.2, DST, version 18, time zone file , KBA , BC-DB-ORA , Oracle , Problem