session timeout not working after roundcube 1.5.5 upgrade.

[jitendra1980]

Dear Team,

We are using Iredmail 1.4.2.We have recently upgraded the roundcube 1.5.5  due to vulnerability issues but now session timeout is not working. It's already there in config.inc.php.

// Session lifetime in minutes
$config['session_lifetime'] = 20;

[JohnDoh]

Please explain what "is not working" means if you want a meaningful response.