I don't think you did anything wrong. As far as with updating I'm really not sure at all but if I were to take a guess, most likely won't cause issues but with feature updates l don't know if it would be worth trying out though most likely the worst that could happen is it would probably simply...
If it runs fine without it could be ok but just to be safe you should probably turn it on. And plus it's good for protecting the system if a rootkit ever infected the boot loader.
Edit: Now that I think of it how exactly did you upgrade? Was it through an in place upgrade? If so where did you...