New WordPress came out last Friday, Sorry about the delay updating the script.
This script will update all instances of wordpress that are not the most current. Run it as root, it will make backups in /root/wp_upgrades of both databases and files in case things go wrong.
It will determine if its a WordPress or WordPress Multi User and apply the correct fix.
wget http://b.ri.mu/files/wordpress-upgrade-2.8.6.sh
sh wordpress-upgrade-2.8.6.sh
You may need to change the ownership of the wordpress files after install, I will fix this bug and write it into the script in the next couple of versions.
If you have any bugs or problems with it, please let me know.