RAV AntiVirus Full Update is the complete database of virus signatures. Update your RAV AntiVirus with the Full Update to have the latest RAV AntiVirus Engine, which will assure the strongest protection against viruses. This update is only for Offline updates. You can always use the Update Feature of your product to make a full update online.
The engine updates are complete updates of the scanning engine, containing the latest daily update. They are recommended only when you haven't updated your product for a long time; full Engine Updates are the best choice in this case because they replace all the files related to the scanning engine, no matter if they need to be replaced or not. If you get the daily updates, there will be no need to use this Full Engine Update.