If you’re using self-hosted WordPress blog (WordPress.org), you might like to check WordPress codex page to find out the “Core Update Host compatibilty feature in WordPress 2.7 work on your webhosting account?” The article is divided into following three sections and lists webhosting companies in alphabetical order. It is important to note that the update feature will not work when updating to Version 2.7, but rather will work for Versions released AFTER 2.7 (e.g. upgrading from 2.7 to 2.7.1)!

• Working Hosts, No Issues
• Works With Caveats
• Doesn’t Work

More info: Core Update Host Compatibility