Cubase Elements 6 questions

i see Cubase Elements 6 is finally released today,great!
I have 3 questions:
1.I was wondering about compatibility between the 3 different versions of C6.I am thinking of installing the Elements 6 version on my Macbook.Will it be able to open a Cubase 6 cpr?Will my third party plug-ins work ok?
2. is there an upgrade path from earlier versions of Cubase to Cubase Elements 6? I have a Cubase 4 LE somewhere ,will i be able to upgrade from this?
3.Do we need a dongle ?

An answer from the moderators would be highly appreciated


It look like basic project compatibility across the C6 range.

I cant think of any reason why pulgins would not work on any of the C6 range.

Yes,i already saw the comparison chart.
But this 'derivate project compatibility ’ is a bit unclear to me…that’s why i would prefer to be sure before buying.
I understand that features missing from Elements won’t show.But will i be able to open the project nevertheless?