This is the announcement in the PHP site, as you can see PHP4 is officially “dead”, so everybody should start the migration to PHP5, read the full post below as extracted from PHP site

“Today it is exactly three years ago since PHP 5 has been released. In those three years it has seen many improvements over PHP 4. PHP 5 is fast, stable & production-ready and as PHP 6 is on the way, PHP 4 will be discontinued.

The PHP development team hereby announces that support for PHP 4 will continue until the end of this year only. After 2007-12-31 there will be no more releases of PHP 4.4. We will continue to make critical security fixes available on a case-by-case basis until 2008-08-08. Please use the rest of this year to make your application suitable to run on PHP 5.

For documentation on migration for PHP 4 to PHP 5, we would like to point you to our migration guide. There is additional information available in the PHP 5.0 to PHP 5.1 and PHP 5.1 to PHP 5.2 migration guides as well. “

In a previous post here in this blog I was talking about the GoPHP5 movement and how as for example Drupal is part of that movement, with these End Of Life announcement the movement is going to grow for sure, and we will start to feel the benefits of PHP5 in our daily applications.