SM 9.50 upgrade patch location?

I'm on SM 9.34 and downloaded SM 9.51 server upgrade.  However, it advises that I can't upgrade from my current version. Reading the doco I found this:

To upgrade the Service Manager server from a version earlier than 9.50 to version 9.51, you must first install Service Manager 9.50, and then upgrade to Service Manager 9.51

However, I can't find 9.50 anywhere on HP's site.  I can find 9.4x and 9.51, but no 9.50.  Does anyone have a link to it?