Nu este necesar de a instala ceva suplimentar pentru a utiliza aceste funcții; ele fac parte din nucleul PHP.

Notă: Getting the latest timezone database

The latest version of the timezone database can be installed via PECL's » timezonedb.

Notă: 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