WordPress 3.3 auto update not working

If you are having problems with the auto upgrade, just download a fresh copy and drag + drop the folders in your FTP client, make sure you select to “merge” so you don’t overwrite your wp-config.php or wp-content folder (in fact take backups!). Then as soon as you go to the wp-admin WP will prompt you to visit an update page.

It’s actually quite tricky to get the permissions perfect for autoupdating, you often get yourself in a situation where you leave your server in a dangerous state (chmod 777 everything) or lock yourself out of editing files (everything owned by server).