This is information on the required PHP/Apache modules that GetSimple uses:

Required Modules (Error)

• SimpleXML - This module is necessary as GetSimple currently relies on XML to store it's data.
  • If you do not have this installed, you will not be able to use GetSimple.

Important but not Required Modules (Warning)

• ZipArchive - This is only needed if you want to take backups of your website.
  • As of GS v3.1, if you do not have this installed, your backups will try to use the zlib library (it will create .tar.gz files instead of .zip)
• Apache mod_rewrite - This is only needed if you want to use FancyURLs (set within the control panel's 'settings' page.)
• Curl - Curl is needed to connect to our API to check for GetSimple updates.
  • This means: you don't really need it, but if you want to install it, see here. (Debian install via apt-get install php5-curl)
• GD Library - This module is needed in order to create thumbnails on uploaded images.