2.4.x patch: http://people.apache.org/~minfrin/httpd-mod_cache-304sanity.patch2.4.patch
+1: minfrin
+ * mod_cache: RFC2616 14.9.3 The s-maxage directive also implies the
+ semantics of the proxy-revalidate directive.
+ trunk patch: http://svn.apache.org/r1479216
+ 2.4.x patch: trunk patch works (minus CHANGES)
+ +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