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I wanted to let you know about this (lack of) code handling but never opened a ticket. This is just a suggestion for future release.
When a profile is deleted, or when an incorrect link is used, jomsocial redirects to the home page. Example
www.site.com/jomsocial/abcdefff
where abcdefff is not a valid profile or group. Hence the code in community.php will do a redirect without a 404 header. This is a bad SEO practice and caused a drop in ranking in search results. Hence I have to hack this code aftery every upgrade. I was hoping you could add a 404 header to prevent soft 404 (which is bad for SEO).