Upgrading to Non-Current Distribution

[Kenneth Jacker]

I am currently running 'natty':

   # lsb_release -a
   Distributor ID:  Ubuntu
   Description:     Ubuntu 11.04
   Release:         11.04
   Codename:        natty


I want to upgrade to the latest *LTS* distribution (12.04),
*not* the latest, "regular" distribution (12.10).

How can I do this?

Tried to find an option to specify a distribution version using
'apt-get', 'aptitude', etc., but could find nothing.  Google
searching didn't turn anything up ... though I might not have search
using the best terms ...

Thanks for your help!
-- 
Prof Kenneth H Jacker       khj at cs.appstate.edu
Computer Science Dept       www.cs.appstate.edu/~khj
Appalachian State Univ
Boone, NC  28608  USA