ORA-56920: a prepare or upgrade window or an on-demand or datapump-job loading of a secondary time zone data file is in an active state

Problem:

During DTS upgrade, while following the steps mentioned here, got the following error:

SQL> DECLARE
  l_tz_version PLS_INTEGER;
BEGIN
  l_tz_version := DBMS_DST.get_latest_timezone_version;
  DBMS_OUTPUT.put_line('l_tz_version=' || l_tz_version);
  DBMS_DST.begin_upgrade(l_tz_version);
END;
/ 

DECLARE
*
ERROR at line 1:
ORA-56920: a prepare or upgrade window or an on-demand or datapump-job loading
of a secondary time zone data file is in an active state
ORA-06512: at "SYS.DBMS_SYS_ERROR", line 79
ORA-06512: at "SYS.DBMS_DST", line 1208
ORA-06512: at line 6

Solution:

The error simply means that this step is already done and you can continue with other steps, make sure that DST_UPGRADE_STATE column in the following query shows UPGRADE value.

SQL> SELECT PROPERTY_NAME, SUBSTR(property_value, 1, 30) value
FROM DATABASE_PROPERTIES
WHERE PROPERTY_NAME LIKE 'DST_%'
ORDER BY PROPERTY_NAME;

PROPERTY_NAME		 VALUE
------------------------ ----------
DST_PRIMARY_TT_VERSION	 32
DST_SECONDARY_TT_VERSION 26
DST_UPGRADE_STATE	 UPGRADE

there is no need to do anything, continue with the next DTS upgrade steps.