For small screens of smartphones, the webmail of Roundcube is not very well suited. That is why there is an alternative now: Rainloop. You can set a “threaded view” in Rainloop, which is also handy for small screens. The Science addressbook is available in Rainloop. One can also use Rainloop for the RU Exchange mail. But Roundcube has many other advantages over Rainloop: manage folders shared with other users, shared labels and the administration of Sieve filters and out-of-office messages. For more information see our mail page.