I've run community/Mage_All_Latest in magentoconnect manager and the module changed to 126.96.36.199 version, however when i go back to admin-panel the magento version at the bottom of the page still says 188.8.131.52. Also if i "check for upgrades" in magentoconnect it seems all has been already upgraded. What is missing?, why the upgrade didn't work. Already clean cache, log-out, then log-in, etc, etc.-
If you have a large installation I would not recommend using Magento connect to upgrade.
Ideally you would rysnc your new files into a dev version of your site with a GIT repo that is running (To capture the changes)
rsync -avz magento1.9/ path/to/dev/site/
The above will over write the core files that need to be upgraded. You can then run the upgrade process.
You can refresh the full process here http://www.magentocommerce.com/wiki/1_-_installation_and_configuration/manual_upgrade_using_fresh_install_and_original_database