Yesterday while I was doing a qa/test on a vm with ns6.7 clean install, I had problems with roundcube.
can anyone confirm this? to replicate install a clean 6.7, update it, install Mail server with all option, then from dashboard > applications click to roundcube webmail
i get, Error 500 in browser, while in /var/log/roundcubemail/errors
"PHP Fatal error: Undefined class constant ‘MYSQL_ATTR_FOUND_ROWS’ in /usr/share/roundcubemail/program/lib/Roundcube/rcube_db_mysql.php on line 151"
to me the solution was to install php-mysql-5.3.3-46.el6_6.x86_64.rpm