To successfully install and use Joomla! you must have a fully operational web server (Apache or IIS), a database (MySQL is the optimum) and the server side scripting language PHP together with specific modules that are activated within PHP for MySQL, XML, and Zlib functionality amongst others.
Joomla! is developed and tested primarily on the Apache web server versions 1.3.x + and 2.x +.
The minimum versions of the various constituent parts of these server components that are required are as follows:
You must ensure that you have the MySQL, XML, and Zlib functionality enabled within your PHP installation. This is controlled within the php.ini file.
Do not use PHP 4.3.9, PHP 4.4.2 or PHP 5.0.4; these releases have known bugs that will interfere with the installation of Joomla! There was also an issue with the Zend Optimizer Version 2.5.10 for PHP 4.4.x. You should ask your host to upgrade to a later release as soon as possible where applicable.
MySQL 6.x is not yet supported.
There are currently ongoing discussions as to whether there are additional issues with the whole 4.3.x. series of releases of PHP. It has been found that the best and most consistent results are achieved with the PHP 5.x series.
Joomla! has been successfully tested on many variants within the main three OS for Windows, Linux, Apple Mac OSX. It may well work on other platforms but this is less well documented.
Joomla! is also regularly used and tested through the main web browsers available such as IE6 +, Firefox 1.5 +, Safari, and Opera but it may also work with others.
There have been known issues with IE6 and certain CSS display settings in template presentation and this should be borne in mind.