ErrorDocument 404 /error.phpin .htaccess and it's always worked fine with 3.0.x
Currently it seems 3.1 is handling 404 errors with
No route found for "GET /other_directory/file_gone.txt"
file or directory has nothing to do with phpbb, yet it's being styled up with a phpbb page info.
It is sending proper headers to browser but it's not very user friendly I think.
:edit: hm, I don't know either but it seems
RewriteRule ^(.*)$ app.php [QSA,L]is the culprit cus it doesn't matter where I set
ErrorDocumentbefore/after top/below in .htaccess.