PHP scripts return the wrong time of day, unless the time zone is set correctly. This article explains how to set up time zones for PHP on IBM i.
The history log is a database file that is tagged with CCSID 65535. The system copies the messages in the QHST message queue to the history log files and then removes them from the QHST message queue.
Working with i5/OS JOBLOG (job logs).
Working with i5/OS OUTQ (output queue)
To safely remove Zend Core from your system after Zend Server for IBM i has been installed, please verify that you are at version 2.6.1 of Zend Core for IBM i5/OS. If you are at an earlier version, please upgrade to 2.6.1 before uninstalling Zend Core for IBM i5/OS. Uninstalling an earlier release of Zend Core for IBM i5/OS will cause ZENDADMIN and other user profiles to be deleted, along with any objects owned by these user profiles. This includes the objects in the Zend Server for IBM i library ZENDSVR.