Ubuntu, the progress in Update Manager does not appear to 11.10 Oneiric. Here's how to solve

Ubuntu releases a new version every 6 months, all this does not mean that we must re-install the OS with every release since we can upgrade to new releases with a "simple" upgrade.
In fact, from our Update Manager will submit the notification of the new version of Ubuntu and will show us if we want to proceed with the 'Our advance version of Ubuntu

Some readers have reported that although the new Ubuntu 11.10 Oneiric has been issued does not appear in any notification manager updates.

Here's how to activate the advance notification of release from Update Manager in Ubuntu.

The problem of lack of notification is most likely due to the package update-manager-core not present, simply launch the terminal and type:

sudo apt-get install update-manager-core
sudo do-release-upgrade

and we will have our advance notification to the new Ubuntu 11.10 Oneiric.

I remember that before the advance is advisable to save our important files.