Jan Koch

Upon activation, this plugin uses the “automatic_updater_disabled” filter to prevent automatic updates from being installed. 
It does not offer configuration, not even an options page in WP Admin.
Simply install and activate the plugin to disable all automatic updates. Deactivate the plugin to re-enable all automatic updates.

Stop Automatic Updates

This plugin disables all automatic updates. No configuration needed.

WordPress.org

Dion Hulse

Andrew Nacin

Most sites are able to apply updates in the background. Background Update Tester checks your site for compatibility and explains any problems.
After activating this plugin, visit the Dashboard → Update Tester screen. (If you are using multisite, visit Updates → Update Tester in the network admin.)
This is an initial release.

Background Update Tester

Most sites are able to apply updates in the background. Background Update Tester checks your site for compatibility and explains any problems.

Stop Automatic Updates vs Background Update Tester