The latest version of PHP can be downloaded from Softpedia
PHP, an HTML-embedded scripting language with syntax borrowed from C, Java, and Perl, with a couple of unique PHP-specific features thrown in, has been updated to version 5.5.7.PHP 5.x includes a new OOP model based on the Zend Engine 2.0, a new extension for improved MySQL support, built-in native support for SQLite, and much more.
According to the changelog, some MIME types have been added to the CLI web server, getallheaders() is now supported by the built-in web server, and invalid constant substitution has been fixed, inconsistent results with require return value have been fixed, and a memory corruption in openssl_x509_parse() has been corrected.
You can check out the official changelog in the readme file incorporated in the source package for more details about this release. Download PHP 5.5.7 right now from Softpedia.