There are many business web applications written in PHP4 that use the Informix module for data access. PHP4 is no longer supported and as a result will not be issued any more fixes or releases. Since version 5.2, the Informix module is no longer available for the PDO module. In this article I'll to describe how to compile and install the Informix module on the Zend Core 2.5 (PHP 5.2.6)