PHP, standing for Personal Home Page, began as a set of Common Gateway Interface binaries written in the C programming language in 1994 by the Danish/Greenlandic programmer Rasmus Lerdorf. Lerdorf initially created these Personal Home Page Tools to replace a small set of Perl scripts he had been using to maintain his personal homepage. The tools were originally created to perform tasks such as displaying his résumé and recording how much traffic his page was receiving. He combined these binaries with his Form Interpreter to create PHP/FI, which had more functionality. It included a larger C implementation which could communicate with databases and helped build simple, dynamic web applications. He released PHP publicly on June 8, 1995 to speed up the finding of bugs and improving the code. This release was named PHP version 2, and already had basic functionality that PHP has today. This includes Perl-like variables, form handling, and the ability to embed HTML. The syntax was similar to Perl but was more limited, simpler, and less consistent.
Zeev Suraski and Andi Gutmans, two Israeli developers at the Technion IIT, rewrote the parser in 1997 and formed the base of PHP 3, changing the language's name to the recursive initialism PHP: Hypertext Preprocessor. The development team officially released PHP/FI 2 in November 1997 after months of beta testing. Afterwards, public testing of PHP 3 began, and the official launch came in June 1998. Suraski and Gutmans then started a new rewrite of PHP's core, producing the Zend Engine in 1999. They also founded Zend Technologies in Ramat Gan, Israel, which manages the development of PHP.
On May 22, 2000, PHP 4, powered by the Zend Engine 1.0, was released. On July 13, 2004, PHP 5 was released and is powered by the new Zend Engine II. PHP 5 included new features such as improved support for object-oriented programming, the PHP Data Objects extension (which defines a lightweight and consistent interface for accessing databases), and numerous performance enhancements. The most recent update released by The PHP Group is for the older PHP version 4 code branch. As of January 2008, this branch is up to version 4.4.8. PHP 4 will be supported by security updates until August 8, 2008.
PHP 5 is the only stable version still being developed. Late static binding has been missing from PHP and will be added in version 5.3.  Development on PHP 4 ceased at the end of 2007, except for the critical security updates for PHP 4 already mentioned. PHP 6 is now under development and major changes include the removal of
register_globals, magic quotes, and safe mode. PHP does not have complete native support for Unicode or multibyte strings; unicode support will be added in PHP 6. Many high profile open source projects ceased to support PHP 4 in new code as of February 5, 2008, due to the GoPHP5 initiative, provided by a consortium of PHP developers promoting the transition from PHP 4 to PHP 5.