Changes in PHP datetime support
Since PHP 5.1.0, there has been an extension named date in the PHP core. This is the new implementation of PHP's datetime support. Although it will attempt to guess your system's timezone setting, you should set the timezone manually. You can do this in any of three ways:
All supported timezones are listed in the PHP Manual.
With the advent of PHP 5.2.x, there are object representations of the date and timezone, named DateTime and DateTimeZone respectively. The methods map to existing procedural date functions.