Evolution 3 finally release and available for ubuntu 11.04 (GNOME), you can install it by adding ppa:gnome3-team/gnome3 to your system's Software Sources (you can use Ubuntu software center/Synaptics Package Manager). Otherways following this step to install Evolution 3 via PPA in Ubuntu

Add Manualy Evolution 3 PPA to your System source (by Mr.Paulo Novais)
deb http://ppa.launchpad.net/danilo/evolution/ubuntu natty main
deb-src http://ppa.launchpad.net/danilo/evolution/ubuntu natty main
Update Software databases 
apt-get update  
Install / Upgrade to Evolution 3
apt-get install evolution
Note : Evolution 3 having dependencies with GNOME 3, so we don't suggested to install it on  except GNOME3.


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