Upgrading to PHP 4.0.3pl1

What is the "proper" way to upgrade from PHP 4.0.2 to PHP 4.0.3pl1 (source)? I have searched across the web, including php.net and zend.com and have found very little on the subject of upgrading/uninstalling PHP (using source on Linux). I have heard people speak of using 'make uninstall' and 'make [dist]clean', and I have heard of people who have simply built a new version of PHP over an old version and had problems. What is the standard and accepted way of upgrading PHP? Should we uninstall the old version (how?) and then build the new version? Or use the makefile in some way to clean up all the stuff from the old version before installing the new version? I am going to be doing this on a live server so I just want to make sure I've done all my homework and know exactly how to proceed before going forward. Thanks for any help. Ryan