I tried to do the upgrade to 3.5.2 and I got to the page which says:
Database Update Required
WordPress has been updated! Before we send you on your way, we have to update your database to the newest version.
The update process may take a little while, so please be patient.
I click update but it does not return. Going back to the wp-admin page, wanting to de-activate plugins and reset the theme to try the upgrade again, forwards to wp-admin/upgrade.php?_wp_http_referer=%2Fwp-admin%2F
I should have avoided this update as the last update took me down as well :-(