Source: https://www.todhost.com/knowledgebase/804/How-to-safely-disable-the-WordPress-automatic-update-feature.html

Beginning from WordPress version 3.7, there were some very exciting features and security patches. This WordPress update became significant as it added the automatic update feature. WordPress now updates itself without asking the user for any conformation or notifications to update.(Note the automatic updates are allowed to update to only minor changes which include security issues i.e. from 3.7 to 3.7.1 and 3.7.1 to 3.7.2 by default, It asks you only conformation when there is a major update i.e. 3.7 to 3. WordPress team had introduced this feature to improve the stability and security of your WordPress installation.

Before you proceed further, you need to check to see if your WordPress installation can run the automatic update. To do this, you will have to install the Background update tester [official link] plugin on your WordPress installation and confirm if your installation meets the requirements for WordPress automatic updates. This will also help you to find out, if your hosting is compatible with WordPress auto-update feature or not.

Automatic Updates

This feature may sound great for normal WordPress users who don't worry about updating their WordPress sites/installation and also it means you can save money that would have been spent on developers you would hire to handle updates for you. (some managed hosting providers update their client's WordPress sites automatically once the updates are available). But when coming to the issues of Developers they are worried as they don't know which update may screw-up the things on the site!. And some developers need some time before getting their plugins ready for the updates.

There are also some professional bloggers and users who would like to update their WordPress site themselves, to know what changes are made in each update to their blogs. So here this post is for the advanced users who really want to stop WordPress automatic updates, And want to have control over the updates on their sites.

There are two methods which can be used to control the automatic updates on a WordPress installation

Method 1:-The Plugin Method

This is simplest and best method to gain some extra control over the updates on your installation. You can get the Updates Option plugin which is developed by George Stephanis and Chip Bennett from WordPress plugin repository[official link] . You can access the settings of updates from Settings-General. This plugin is best for those who don't want to touch the code and need to be done quick.

Update Plugin gives all the options of the Automatic Updates in simple drop box menu. If you don't want to mess with option and just want to disable the automatic updates then you can simply opt for NO option at Automatic Updates Enabled?. This plugin not only offers automatic WordPress core files updates control, it also supports the update control over the plugin and themes updates

Method 2:- Configuring wp-config file

This second option is a little advanced when compared to the above method. If you want to disable all the WordPress updates including the minor and major core updates then add this code as it is in the wp-config.php

define( "WP_AUTO_UPDATE_CORE" false );

If you want to enable the minor and major both the automatic updates then add the below code.

define( WP_AUTO_UPDATE_CORE, true );

If you want to restore to default value i.e to enable the WordPress installation only for the minor updates then use the below code line.

define( WP_AUTO_UPDATE_CORE);

The preference is for the user to choose which option best suits his need. Most newbie will prefer the plugin method as it is safer and does all the job neatly. Most developers will editing the WP-config method, as it takes off the burden of adding another WordPress plugin to the blog.

Remember to maintain a functional and complete backup of your WordPress blog every day, to avoid any future issues with WP auto update.