Last wordpress version supported

Hello,

I really like this theme, but can’t have it entirely working. I have some questions.
1)Is the last version of wordpress supported? Because I can’t see submenu items.
2)Where can we edit the home page headlines?
Also I was wondering if it is possible to:
3) Add a subtitle in the header under the title (the header size would then increase).
4) Add a «subscription to newsletter» widget in the header
5) Add more headlines and text in the home page?

Regards,

Cédric