external.php - excludes specific forum categories

[criscokid]

I'd like edit the RSS external.php file so that it excludes specific forum categories - not sure what part of the code I need to edit though.

[calorie]

You could set forumids=1,2,3 in the query string for forums you want to appear, or you could make a plugin at the external_start hook, and set $forumids = '1,2,3'; for the forums you want to appear regardless of what comes in via query string.

[criscokid]

On second thoughts being 'forum specific' (rather than exclude forums) is better for me. I'd forgotten you can specifiy forums in the URL.

"you could make a plugin" - never done this before so I'd have to read up on it.