Apache HTTP server
Version 5.5 and above
Version 5.4.0 and above
Recommended version : latest from 5.5.x branch.
Version 1.11.0 and above, compatible with ZF 1.12.x
DotKernel recommends that Zend Framework be installed as a PEAR package on the server: https://www.dotkernel.com/zend-framework/zend-framework-pear-plesk-server/ or at least to be accessible in include_path.