Minimum Requirements

• Joomla! 1.7.2+, 2.5
• PHP 5.2.x+
• PHP GD 2.0+ Extension
  • Usually every hosting provider have activated this.
  • Is required for JYAML::getImage().
• PHP cURL Extension (optional, but recommended)
  • Normally is activated at any good hosting provider.
  • Is required for the JS CSS Chunker
  • Is required for the Upgrader (only if allow_url_fopen is disabled in the php.ini)

Supported browsers

• Internet Explorer 7+
• Mozilla Firefox 3+
• Google Chrome 4+
• Apple Safari 4+
• Opera 9+
• Konqueror 4+
• All other Webkit2+ and Gecko2+ based Browsers
• Textbrowser (like Lynx)

The Internet Explorer 6 officially is no longer supported (by Joomla! itself also). Basically it works, but there have certain limitations.