[Zope] ProxyVia patch

Quick question... Is the ProxyVia patch shown on page... http://www.zope.org/Members/unfo/apache_zserver_ssl ...a change to ProxyVia in Apache, or is it to add ProxyVia to some old version of Apache which didn't have it already? I have Apache on a Cobalt server and don't fancy re-compiling it. I have ProxyVia turned on but ZWiki doesn't completely work (Zope 2.3). Do I need to apply this patch to fix it? What would happen if I didn't? I know that's a few questions but if anyone can answer even one of them I would be most grateful. Regards, Simon.