Как сделать strong вместо b в dle 10.6?

$txt = str_replace( "<b>", "[b]", str_replace( "</b>", "[/b]", $txt ) );

$txt = str_replace( "<strong>", "[strong]", str_replace( "</strong>", "[/strong]", $txt ) );

            while( preg_match( "#\[(b|i|s|u|sub|sup)\](.+?)\[/\\1\]#is", $source ) ) {
                $source = preg_replace( "#\[(b|i|s|u|sub|sup)\](.+?)\[/\\1\]#is", "<\\1>\\2</\\1>", $source );
            }

            while( preg_match( "#\[(b|strong|i|s|u|sub|sup)\](.+?)\[/\\1\]#is", $source ) ) {
                $source = preg_replace( "#\[(b|strong|i|s|u|sub|sup)\](.+?)\[/\\1\]#is", "<\\1>\\2</\\1>", $source );
            }