Many users are asking us how to enable automatic updates in WordPress. For the moment, there is no option in the WordPress admin panel. You must enable this option by editing the configuration file – wp-config.php.
The line that needs to be added to the bottom of the wp-config.php file to enable automatic minor and major updates is:
define( 'WP_AUTO_UPDATE_CORE', true );
More info on the WP_AUTO_UPDATE_CORE option from the WordPress site:
WP_AUTO_UPDATE_CORE can be defined with one of three values, each producing a different behavior:
Value of true – Development, minor, and major updates are all enabled
Value of false – Development, minor, and major updates are all disabled
Value of ‘minor’ – Minor updates are enabled, development, and major updates are disabled
Notice: WordPress will update itself to a development release ONLY if you already are using such a release.
The video tutorial for this article:
References:
https://codex.wordpress.org/Configuring_Automatic_Background_Updates