Cloud Office Premium gives you 25 GB of mailbox storage. In addition to standard features such as e-mail, calendar, contact management, etc., you also get premium benefits such as ActiveSync with mobile devices and Cloud Office Drive for online file and document management.
Cloud Office Premium is available for just CHF 7 per month per user.
You can upgrade to Cloud Office Premium directly in the Control Panel. Log into your Control Panel, go to the E-mail category and click on Edit next to the desired e-mail address. Activate Cloud Office Premium there.