PHP >= 4.2.x (including PHP 5.x); Microsoft IIS requires PHP 5.x
MySQL >= 3.23.23 (including MySQL 4.x and 5.x) or PostgreSQL >= 7.1 (including PostgreSQL 8.x)
Apache >= 1.3.2x or >= 2.0.4x or Microsoft IIS 6
Operating system: Any OS that supports the above software, including Linux, BSD, Solaris, Mac OS X, Windows
We also recommend that you have SSH access to your server, as you will find SSH access mandatory for some advanced tasks, and helpful overall.