Upgrade to Mac Yosemite

Hi all,
I am currently working on Cubase 7.5.0 Build 114 - 32 bit
My OS is Mac OS X version 10.9.5
My sound interface is a Focusrite Scarlett 6i6

What is the best way to upgrade to Yosemite ? Is my Cubase version compatible with Yosemite ?
Do I have to upgrade Cubase to 7.5.40 first ? What comes first, OS or Cubase upgrade ?

Thanks in advance.

Luc De Kesel