Migrating from PHP 5.0.x to PHP 5.1.x
PHP Manual

Date/time support

Date/time support has been fully rewritten in PHP 5.1.x, and no longer uses the system settings to 'know' the timezone in operation. It will instead utilize, in the following order:

  • The timezone set using the date_default_timezone_set function (if any)

  • The TZ environment variable (if non empty)

  • "magical" guess (if the operating system supports it)

  • If none of the above options succeeds, UTC

To ensure accuracy (and avoid an E_STRICT warning), you will need to define your timezone in your php.ini using the following format:

date.timezone = Europe/London

The supported timezones are listed, in this format, in the timezones appendix.

Also note that strtotime now returns FALSE on failure, instead of -1.