The repositories are the same between the different flavors of Ubuntu. So regardless of which one you use, you will still have the same verion of Midori (currently at 0.19 in the Universe repositories).
If you want to get the latest verion, then you will need to add the ppa for midori and for webkit.
You need to open a terminal, and then enter the following commands:
First you add the ppas
And then you update:
sudo add-apt-repository ppa:midori
sudo add-apt-repository ppa:webkit-team
You might have to reinstall webkit
sudo apt-get update
sudo apt-get upgrade
If you get problems with the new repositories, you probably need to sign them:
sudo apt-get install webkit
Followed by the update.
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 2D9A3C5B
sudo apt-key adv --recv-keys --keyserver keyserver.ubuntu.com A69241F1
Hope this helps.