My friend has a WP setup, 1.5.2, and I have my blog running 1.5.1.2
Whenever she places a trackback it seems to go through to a lot of blogs, but not mine, it never shows up. I have all the options turned on, are there any issues with 1.5.2 -> 1.5.1.2 trackbacks?
Thanks!
Someone may correct me, but I think there were simply problems with trackbacks in 1.5.1.2. Have you tested them via Podz's test site?
http://www.tamba2.org.uk/wordpress/TestTrack/index.php
Unless there's a specific reason you haven't upgraded, I think the advantages (security) outweigh any reason not to.