To update, you need to get the files onto your server and then package manager will see the new versions.
I do this by symlinking to whatever the current verision is. If you use cvs there are other ways.
ALso, if you do the symlink, make sure you move all your assest etc. A little more work once or twice a year, but I got tired of CVS for my sites. I am by myself and don't really need all the revisons.
