design, model, present, analyze, realize...
Owners of Rhino 4 are encouraged to download Service Release 9.
Service releases have bug fixes and minor enhancements. They are only available on the Internet. Updating to the current service release is not always critical, unless you're experiencing problems listed on the service release notes.
Each service release contains all prior service releases.
This is a patch installer. It will only install if you have a previous installation of Rhino 4 (not beta or evaluation versions) installed.