Non รจ necessaria nessuna installazione per usare queste funzioni, esse fanno parte del core di PHP.
Nota: Getting the latest timezone database
The latest version of the timezone database can be installed via PECL's » timezonedb.
Nota: Experimental DateTime support in PHP 5.1.x
Although the DateTime class (and related functions) are enabled by default since PHP 5.2.0, it is possible to add experimental support into PHP 5.1.x by using the following flag before configure/compile: CFLAGS=-DEXPERIMENTAL_DATE_SUPPORT=1