No there wont be an internal update from 2.0 to 2.1 yet and im not sure, if there will be internal update at all.
The Installer of 2.1 will detect the previous version and ask you, if you want to remove it. - I recommend you to answer this question with yes. (You will need to restart your computer)
So you can install 2.1 version over 2.0, because the Installer of 2.1 will detect the previous version.