http://www.xoops.org/modules/newbb/viewtopic.php?post_id=286047
I added this code to the template "system_rss.html" to make RSS feeds 100% compatible with all aggregators:
Line 2 - after xml version:
<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">
Line 14 - after channel language:
<atom:link href="<{$xoops_url}><{$smarty.server.REQUEST_URI}>" rel="self" type="application/rss+xml" ><="" p="">
I use the above smarty code because hardcoding the self-address of your rss feed (eg. "http://mydomain.org/backend.php") will break your feed in other modules that use backend.php to generate RSS feeds (namely wf-downloads).
Can these changes be added to a following release?