If the Pre-Upgrade Information Tool instructs you to upgrade the time zone files after completing the database upgrade, then use the DBMS_DST PL/SQL package to upgrade the time zone file.

Oracle Database supplies multiple versions of time zone files. There are two types of files associated with each time zone file: a large file, which contains all the time zones defined in the database, and a small file, which contains only the most commonly used time zones. The large versions are designated as timezlrg_version_number.dat. The small versions are designated as timezone_version_number.dat. The files are located in the oracore/zoneinfo subdirectory under the Oracle Database home directory.