php5 to php4 downgrade problem

[leventd]

I know'nt make a for doqngrade php5 to php4. How can i downgrade php5 to php4 on plesk 8.6? Please helpme for this problem... Thanks for all...


[root@server yedek]# php -v
PHP 5.1.6 (cli) (built: Apr 7 2009 08:00:04)
Copyright (c) 1997-2006 The PHP Group
Zend Engine v2.1.0, Copyright (c) 1998-2006 Zend Technologies


[root@server yedek]# rpm -qa |grep php
php-mbstring-5.1.6-23.2.el5_3
psa-php5-configurator-1.4.0-cos5.build86080722.00
php-imap-5.1.6-23.2.el5_3
php-common-5.1.6-23.2.el5_3
php-cli-5.1.6-23.2.el5_3
php-pdo-5.1.6-23.2.el5_3
php-gd-5.1.6-23.2.el5_3
php-5.1.6-23.2.el5_3
php-mysql-5.1.6-23.2.el5_3
php-xml-5.1.6-23.2.el5_3