As per my previous post about v1.0.1 with:
Quote// enforce connections over https
// with this option enabled, all non-secure connections will be redirected.
// set the port for the ssl connection as value of this option if it differs from the default 443
$config['force_https'] = true;
// tell PHP that it should work as under secure connection
// even if it doesn't recognize it as secure ($_SERVER['HTTPS'] is not set)
// e.g. when you're running Roundcube behind a https proxy
// this option is mutually exclusive to 'force_https' and only either one of them should be set to true.
$config['use_https'] = false;
Results in an endless redirect loop, worked fine with v1 and lower.