Many thanks to Gertjan in forum https://forum.pfsense.org/index.php?topic=87504.msg484017#msg484017 Specifically setting the output encoding to latin-1 was causing the "black diamonds" for special characters in the http://blog.pfsense.org RSS feed (e.g. the registered trademark sign after pfSense did not come out). It should all work by letting simplepie do its default stuff with the RSS feed.
Remove latin-1 encoding of RSS feed
Many thanks to Gertjan in forum https://forum.pfsense.org/index.php?topic=87504.msg484017#msg484017
Specifically setting the output encoding to latin-1 was causing the "black diamonds" for special characters in the http://blog.pfsense.org RSS feed (e.g. the registered trademark sign after pfSense did not come out).
It should all work by letting simplepie do its default stuff with the RSS feed.