SaaS edition is a yearly subscription that includes free automatic upgrades.
Standard edition is a one time purchase of the software and includes no technical support or upgrade path.
Extended Edition is the same software package as Standard Edition but includes a full year of free technical support and software updates including the next major version free. Extended Edition also includes the Extended Edition Upgrade option for a yearly software upgrade and technical support at one quarter of the regular price.
This is an upgrade to the most recent version of the software package. This option is only available to clients who have licensed the Extended Edition version.