[NTLDR]

This is the simplist method of doing this, in global.php find:

PHP Code:

// is style in the forum/thread set?
if ($codestyleid)
{ 


Add before (replace X with the upgraded users usergroupid):

PHP Code:

if ($bbuserinfo['usergroupid'] == X) {
    $vboptions['allowchangestyles'] = 0;
}