roundcube: Throws 500 error on demo server
Accessing https://demo.freedombox.org/roundcube throws a 500 error and shows a blank page to the user.
Error log from /var/log/roundcube/errors
[04-Apr-2019 09:33:01 UTC] PHP Warning: session_start(): Failed to read session data: user (path: /var/lib/php/sessions) in /usr/share/roundcube/program/lib/Roundcube/rcube_session.php on line 129
[04-Apr-2019 09:33:01 UTC] PHP Fatal error: Uncaught Error: Undefined class constant 'MYSQL_ATTR_FOUND_ROWS' in /usr/share/roundcube/program/lib/Roundcube/rcube_db_mysql.php:144
Stack trace:
#0 /usr/share/roundcube/program/lib/Roundcube/rcube_db.php(153): rcube_db_mysql->dsn_options(Array)
#1 /usr/share/roundcube/program/lib/Roundcube/rcube_db.php(138): rcube_db->conn_create(Array)
#2 /usr/share/roundcube/program/lib/Roundcube/rcube_db.php(231): rcube_db->dsn_connect(Array, 'w')
#3 /usr/share/roundcube/program/lib/Roundcube/rcube_db.php(417): rcube_db->db_connect('w', true)
#4 /usr/share/roundcube/program/lib/Roundcube/rcube_db.php(380): rcube_db->_query('SELECT `vars`, ...', 0, 0, Array)
#5 /usr/share/roundcube/program/lib/Roundcube/rcube_session_db.php(99): rcube_db->query('SELECT `vars`, ...', '9kj53no9th3pbga...')
#6 [internal function]: rcube_session_db->read('9kj53no9th3pbga...')
#7 /usr/share/roundcube/program/lib/Roundcube/rcube_session.php(129): session_start()
#8 /usr/share/roundcube/program/lib/Roundcube/rcube.php(532): rcube_session->start( in /usr/share/roundcube/program/lib/Roundcube/rcube_db_mysql.php on line 144