WordPress 3.7 has introduced a new feature where the core wordpress will be automatically upgraded to the minor releases. For example, any site running 3.7 will get automatically upgraded to 3.7.1 when it is released (you won’t have to click the upgrade now link to initiate the upgrade process).
Some users may not want this feature even though the background upgrades should be smooth.
You can add the following constant definition in your wp-config.php file which will turn off this auto background upgrade feature:
define( 'AUTOMATIC_UPDATER_DISABLED', true );
This will make your wordpress site behave like it used to before. When there is an upgrade, it will show a notification in the admin dashboard header area and you can click on the link to upgrade when you want to.
If you are a developer and you want to control this via a plugin or theme then you can use the following filter to override this.
automatic_updater_disabled
This filter will override the constant value set in the wp-config file.