The Zend Optimizer is a free runtime application that enables PHP to run the files encoded by the Zend Guard. This can be freely used by anyone looking to run encoded applications. Zend Optimizer is bundled within Zend Core along with a certified copy of PHP containing the latests bug fixes, Zend's FastCGI technology, a copy of MySQL or DB2 Express-C, and an Apache web server for a easy to install stack.; Zend Core Support Subscription, gives you access to an automated downloads of security and critical fixes and other support features that real PHP applications require.