WordPress.org

Completely disables the theme update checking system in WordPress 2.8 and later. The plugin prevents WordPress from checking for updates, and prevents any notifications from being displayed on the Themes page. Ideal for administrators of multiple WordPress installations.

Please note!

It's important that you keep your WordPress themes up to date. If you don't, your blog or website could be susceptible to security vulnerabilities or performance issues. If you use this plugin, you must make sure you keep yourself up to date with new releases of your themes and update them as new versions are released.