PHP 4 End of Life Announcement
The PHP development team, on 13-July-2007, has announced End of Life for PHP4. As per the notice on www.php.net support for PHP4 will continue till 31-Dec-2007 only.
Hence it is strongly suggested that you ask your development team to make your website suitable to run on PHP 5. For documentation on migration from PHP4 to PHP5, please check migration guide available on PHP website (www.php.net).