Please use the Upgrading Notification Services 2.0 Instances to Notification Services 2.0 SP1 link.

The Upgrading Notification Services 2.0 Instances to Notification Services 2.0 SP1 download link will start or launch the vendor software form.

Notification Services 2.0 SP1 is a full release of Notification Services. If you have existing Notification Services 2.0 applications, and you want to upgrade them to SP1