I can not find the security mailing list and security yum and apt repository for Carbonio CE.
Zimbra has been known to have zero-day exploits and relies on many components with security issues.
It is important to have a new patch available and be informed by mailing/forum within 24 to 48 hours and be able to install and test this through a package manager so changes/packages can be automatically applied and downgraded when necessary.
Could Carbonio CE create a security mailing-list or security page on the forum to subscribe to, as an alternative to the Zimbra patch mailings that come out. And could Carbonio CE make patches available not at the end of every month but when needed for security.
Also releasing new features every month, there should be a mailing/change-list somewhere that keeps track of this, new features are generally not very welcomed by endusers, especially not every month.