$optionalsubsystems->add(new admin_setting_configcheckbox('messaginghidereadnotifications', new lang_string('messaginghidereadnotifications', 'admin'), new lang_string('configmessaginghidereadnotifications','admin'), 0));
$optionalsubsystems->add(new admin_setting_configselect('messagingdeletereadnotificationsdelay', new lang_string('messagingdeletereadnotificationsdelay', 'admin'), new lang_string('configmessagingdeletereadnotificationsdelay', 'admin'), 604800, $options));
$string['configmaxevents'] = 'Events to Lookahead';
$string['configmessaging'] = 'If enabled, users can send messages to other users on the site.';
$string['configmessagingallowemailoverride'] = 'Allow users to have email message notifications sent to an email address other than the email address in their profile';
$string['configmessaginghidereadnotifications'] = 'Hide read notifications of events like forum posts when viewing messaging history';
$string['configmessagingdeletereadnotificationsdelay'] = 'Read notifications can be deleted to save space. How long after a notification is read can it be deleted?';
$string['configmessagingallusers'] = 'If enabled, users can choose to allow anyone on the site to send them a message. Otherwise, users can choose to allow only their contacts or others in their courses to send them messages.';
$string['configminpassworddigits'] = 'Passwords must have at least these many digits.';