http://people.apache.org/~minfrin/httpd-mod_cache-olderdate2.4.patch
+1: minfrin
+ * mod_cache: If a 304 response indicates an entity not currently cached, then
+ the cache MUST disregard the response and repeat the request without the
+ conditional.
+ trunk patch: http://svn.apache.org/r1481197
+ http://people.apache.org/~minfrin/httpd-mod_cache-uncacheable304-2.4.patch
+ +1: minfrin
+
A list of further possible backports can be found at:
http://people.apache.org/~rjung/patches/possible-backports-httpd-trunk-2_4.txt