We are using Magnolia CE 3.6.3 and we have an issue with handling
if-modified-since headers. To illustrate :

jon@ubuntu:~/tests$ wget --header='If-Modified-Since: Tue, 1 Jan 2008 19:58:25 GMT' http://localhost:8180/magnoliaPublic/help/services.html
-16:35:59- http://localhost:8180/magnoliaPublic/help/services.html
=> `services.html'
Resolving localhost... 127.0.0.1
Connecting to localhost|127.0.0.1|:8180... connected.
HTTP request sent, awaiting response... 304 Not Modified
16:36:39 ERROR 304: Not Modified.

So basically magnolia is saying content has not been modified since Jan
1st this year, which is just plain wrong.