1) What seems to be the problem?
I've followed your link in your signature and your forum looks fine upon first inspection.
http://www.dragonclan-forum.de/board/ubbthreads.php/forum_summary(attached screenshot)
The majority of changes between 7.5.x -> 7.6.x were related to updating the html/css to responsive, so that it would display properly on all screen sizes. Desktop and mobile.
The bit of code you've shared is what I assume is the content of your customized
/includes/header.php file. I see that you are declaring strings in there which are already declared within the main /libs/html.inc.php and /libs/ubbthreads.inc.php files. There is no reason for duplication of them.
2) What exact version of UBB.threads did you upgrade from? Knowing that may also be helpful.
Thanks
e1: /includes/header.php is customized within Control Panel / General: HTML Includes / Default Header
e2: the information posted at this link might be helpful to you if you have custom styles. especially the "STYLE ADJUSTMENTS, WHEN UPGRADING FROM UBB.threads 7.5.x to 7.6.x" section under "STYLES - ADVANCED".
https://www.ubbcentral.com/forums/u...re-7-6-0-changelog-discussion#Post259088
