[users] how to update from 2.0 to 2.2

[Cephas]

I just downloaded v.2.0 last week and  am still learning my way  around.
Just recieved email on new version 2.2
Opened officeorg looking for update button, couldn't find one.
Went to main site and it appears that I have to download whole new version.  
Appox 200MB.
If this is correct, should I uninstall v.2.0 first?
If not how do I update?
Shouldn't there be an update button or link?