[ovirt-users] Difference between edit cluster and upgrade?

Hello, supposing I upgrade my env from 4.3 to 4.4. Then I can update my clusters' compatibility from 4.3 to 4.5. I can do it in two ways: 1) select cluster line, "edit" button and change "Compatibility Version" from 4.3 to 4.5 2) select cluster line, "upgrade" button correct? What is the difference? Thanks, Gianluca