To find the Applications/Versions/Patch Levels are loaded in the Oracle Apps Instances

SELECT   SUBSTR (a.application_name, 1, 60) "Application Name",
         SUBSTR (i.product_version, 1, 4) "Version",
         i.patch_level "Patch Level", i.application_id "Application ID",
         i.last_update_date "Last Update"
    FROM apps.fnd_product_installations i, apps.fnd_application_all_view a
   WHERE i.application_id = a.application_id
ORDER BY a.application_name;

How to find your gl period end date

SELECT gps.end_date
  FROM gl_period_statuses gps
 WHERE gps.application_id = '222'
   AND gps.closing_status = 'O'
   AND gps.start_date =
            (SELECT MAX (gpss.start_date)
               FROM gl_period_statuses gpss
              WHERE gpss.application_id = '222' AND gpss.closing_status = 'O');