Users of Zorin OS 4 may be prompted to upgrade to Ubuntu 11.04. We strongly urge you not to do so as the upgrade process may render your install unusable.
We are already working on the next version of Zorin OS (5) which is due to be released by the end of May 2011. Zorin OS 5 will be based on Ubuntu 11.04 but it will use the Classic GNOME desktop environment instead of Ubuntu’s new Unity or GNOME Shell. Please wait for this new release to enjoy all of the new updates and enhancements in this new release.